The Islamist group, Boko Haram, says it carried out Thursday's bombing of Nigeria's police headquarters which left at least six people dead.
The attack comes days after Nigeria's police chief visited the north-eastern town of Maiduguri, where Boko Haram is based and vowed to defeat the group.
The police say one of those who died was a suicide bomber - if confirmed it would be Nigeria's first such attack.
Boko Haram wants to overthrow the state and implement Islamic law.
In 2009, hundreds of Boko Haram supporters, including the group's leader Mohammed Yusuf, were killed after they attacked police stations in Maiduguri and other northern towns.
The group has since reformed and in the past year has killed dozens of police officers, politicians and anyone who criticises it, including Christian preachers and clerics from other Muslim groups.
It has also said it planted several bombs which went off in Abuja and other states after President Goodluck Jonathan's inauguration last month.
"We are responsible for the bomb attack on the police headquarters in Abuja which was to prove a point to all those who doubt our capability," said a statement from the group.
President Goodluck Jonathan on Friday visited the scene of the blast and urged Nigerians not to panic.
He said all countries were affected by "terrorist attacks".
The president was accompanied by police chief Hafiz Ringim, who may have been the target of the attack.
'Windows shaking'
The BBC's Jonah Fisher in Lagos says that, for the Nigerian authorities, the attack is an embarrassing strike at the very heart of their security establishment.
Inspector General Hafiz Ringim went to Maiduguri earlier this week, taking reinforcements and promising that the Boko Haram problem would be solved within months.
Our correspondent says the group's response was delivered directly to police head office in Abuja.
Less than two minutes after Inspector General Ringim arrived for work on Thursday morning, a car that had been following closely behind his vehicle exploded in the car park.
Our correspondent says it is still unclear whether the driver of the car intended to die in the blast.
The blast in the car park of the police base also destroyed many vehicles and a large plume of smoke could be seen rising from the scene.
Residents say the explosion was heard across the city.
"My windows were shaking and I heard the loud noise. I saw smoke coming up," Reuters news agency quotes one witness as telling a local television station.
A bus commuter who saw the blast told the BBC's Focus on Africa programme: "All of a sudden there was this loud explosion. Everybody was scared and people began to run around."
He said police and Red Cross officials had rushed to the scene, and had moved people away from the area.
The police said 33 cars had been damaged beyond repair and 40 more had been partially damaged by the explosion.
The Boko Haram sect accuses Nigeria's government of being corrupted by Western ideas and wants to overthrow the state and impose Islamic law on the country.
It has killed dozens of people, mostly shot by gunmen riding motorbikes, in Maiduguri, the capital of Borno state.
Former IMF chief Dominique Strauss-Kahn complained about being handcuffed and initially claimed diplomatic immunity when he was arrested for sexual assault in New York, official documents reveal.
He has since resigned from the IMF and is living on bail in New York.
He has pleaded not guilty to charges of sexual assault on a hotel chambermaid.
His lawyer, Benjamin Brafman, refused to comment on the release of the transcripts.
Airport ruse
The transcripts reveal details of how hotel staff and police investigators managed to detain Mr Strauss-Kahn as he attempted to leave the country on an Air France jet.
As has previously been reported, Mr Strauss-Kahn phoned the Sofitel Hotel about 1530 local time (1930 GMT), saying he had left his mobile phone.
While police listened in, the hotel promised to return it to him at the Air France terminal at JFK International Airport. Instead, police arrived to arrest him.
At the airport police station, detectives ordered Mr Strauss-Kahn to empty his pockets, the documents show, followed by this exchange:
Detective Maharaj: "Please have a seat."
Defendant: "Is that [handcuffing] necessary?"
Det Maharaj: "Yes, it is."
Defendant: "I have diplomatic immunity."
Det Maharaj: "Where is you passport?"
Ten minutes later, Mr Strauss-Kahn asked if he could be handcuffed "in the front", and five minutes after that, he said, "I need to make a call and let them know I won't be at my meeting tomorrow. These handcuffs are tight."
Breakfast
Five hours later, at 2100 (1600 GMT) at Manhattan Special Victims Squad:
Defendant: "Do I need a lawyer?"
Detective Rivera: "It is your right to have one in this country if you want. I don't know if you have some kind of diplomatic status."
Defendant: "No, no, no. I'm not trying to use that. I just want to know if I need a lawyer."
Det Rivera: "That is up to you."
Several days after his arrest, the IMF said Mr Strauss-Kahn, as managing director, had only limited immunity that was not applicable in the New York case.
Two hours after Mr Strauss-Kahn asked whether he needed a lawyer, he told the detectives the lawyer had told him not to talk.
The following morning, the transcript shows Mr Strauss-Kahn asking for some eggs for breakfast, followed by a sandwich.
The tech world is in the middle of the "cloud" wave, but it's potential could be complicated by another looming trend -- plans that cap how much data you can use through your home broadband connection.
After wishing for a tweak to Gmail that would repost received messages at later dates, Boomerang, a free Gmail plug-in, offers to do that and a whole lot more.
A new survey notes that customers who use Netflix streaming video are twice as likely to cancel or slim down their cable services as they were this time last year.
Fresh demonstrations against President Bashar al-Assad's regime have erupted across Syria, with reports of at least eight people killed by security forces.
Activists and witnesses said security forces had opened fire in Homs, Damascus, and Deir al-Zour in the east.
Official media played down the size of the protests, but said a number of policemen had been shot and wounded.
Earlier, the Syrian army moved into two northern towns as it seeks to end months of anti-government protests.
Tanks, armoured personnel carriers and buses were used to secure Maarat al-Numan and Khan Sheikhoun, both on the road linking Damascus and Aleppo.
The EU is pressing for a new round of sanctions against Syria.
The UN says that at least 1,100 people have died as the government has cracked down on demonstrations that began in March.
Syrian rights groups put the overall death toll in Syria at 1,297 civilians and 340 security force members.
'Arresting the wounded'
Syria has prevented foreign journalists, including those from the BBC, from entering the country, making it difficult to independently verify reports from there.
But activists and witnesses said security forces had opened fire on demonstrators in several locations.
Witnesses told the BBC that there was a huge demonstration around the al-Nour mosque in Homs.
One resident of Homs said: "My friend has just called me from Khaldea to tell me that one of the protesters there has been killed. I know that another 15 people have been injured too.
"They are even arresting the wounded and taking them to the military hospital," he said.
Activists said there had also been deaths in Damascus, the eastern provincial capital of Deir al-Zour, and the province of Deraa in the south.
In Deir al-Zour, witnesses and residents told Reuters news agency that two protesters were shot dead as they tried to rip down posters of the president.
Witnesses told the BBC that there had been protests in several districts of Damascus. Protesters have placed tyres and stones as roadblocks near the Abu Bakr mosque in the al-Qaboun neighbourhood, they said.
Activists dedicated Friday's protests to Saleh al-Ali, who fought against French colonial rule in the early 20th Century.
Syria's government has blamed the unrest on "armed gangs" and foreign meddling.
State TV reported on Friday that one policeman had been killed and 20 wounded during an attack by "armed groups" in Deir al-Zour.
Fleeing into Turkey
President Assad is facing the gravest threat to his family's 40-year ruling dynasty, as unrest that first erupted in the south of the country has now engulfed the north - near the border with Turkey - and is threatening to spread eastwards towards its border with Iraq.
State television has shown pictures of troops moving into Maarat al-Numan, which is some 40km (25 miles) south-east of Jisr al-Shughour, the town overrun by tanks and troops on Sunday.
It said the army had also moved into Khan Sheikhoun, just south of Maarat al-Numan, to prevent what it called "armed terrorist organisations" from cutting off the highway.
Officials said they were planning a "limited military operation" in Maarat al-Numan to restore security there.
One resident told BBC Arabic the town was very tense and dominated by a "sense of fear".
At least 9,000 Syrian refugees have now fled across the border into Turkey, and Ankara says it will supply humanitarian aid to some 10,000 people who are stranded on the Syrian side of the border.
Are you in Syria? What is your reaction to events? Send us your comments using the forms below.
Send your pictures and videos to yourpics@bbc.co.uk or text them to 61124 (UK) or +44 7725 100 100 (International). If you have a large file you canupload here.
Greek Prime Minister George Papandreou has vowed to fight on in seeking support for new austerity measures that have sparked strikes and protests.
Greek ruling party deputies are holding an emergency meeting to discuss the crisis that has shaken global markets.
To a standing ovation, Mr Papandreou said he would reshuffle his cabinet before putting it to a vote of confidence by the parliament.
He was speaking after some figures in his party appeared to move against him.
"I seek and will continue seeking wider consensus," said Mr Papandreou. "Our response to the challenges we face is stability and to stay on our course of reforms."
The proposed measures are necessary to gain EU and IMF aid, but have been met with fierce opposition inside Greece.
Athens witnessed some of the most violent protests in more than a year on Wednesday, as demonstrators went on to the streets and took part in a general strike.
More time?
Mr Papandreou faces the threat of a revolt in his socialist Pasok party over the controversial package, with two deputies resigning on Thursday in protest against the proposed austerity measures.
The EU leaders are at loggerheads over the issue: should Greece be allowed to do a soft, controlled, partial default on its debts which forces banks and pension funds to lose some of the money they lent to Greece?”
End QuotePaul MasonEconomics editor, BBC Newsnight
The resignations do not affect the party's five-seat parliamentary majority as the seats are automatically allocated to the next Socialists in line, but they are an indication of the difficulties Mr Papandreou faces in winning confidence in his leadership, says the BBC's Malcolm Brabant in Athens.
President Karolos Papoulias has urged Greek politicians not to make matters worse by turning the economic crisis into a political one.
A confidence vote in the new cabinet is expected on Sunday, reports say.
This would give the EU more time to finalise a package to help Greece.
Assuming that some form of Greek government emerges out of the political discussions now under way in Athens, it is now almost certain that Greece will get the official money it needs to stay above water for a few more weeks, notably the next tranche of last year's EU-IMF bailout, says the BBC's economics editor, Stephanie Flanders.
All the eurozone ministers have to do is agree in principle to fill the funding gap in the Greek economic programme, which they will now do on Sunday, adds our correspondent.
The IMF is expected to pay the next tranche of Greek aid of 12bn euros ($17bn) on the basis of a promise of future EU funding rather than any concrete commitments.
Greek Prime Minister George Papandreou is set to announce a new cabinet in a concessionary move as he seeks support for new austerity measures.
Mr Papandreou, who will stay in his post, says he will put the cabinet to a vote of confidence in the parliament.
Renewed fears that Greece will default on its debt have shaken markets.
Greek ruling party deputies are set to hold an immediate emergency meeting of their parliamentary group to discuss the current crisis.
President Karolos Papoulias has urged Greek politicians in a statement not to make matters worse by turning the economic crisis into a political one.
The proposed measures are necessary to gain EU and IMF aid, but have been met with fierce opposition in Greece.
Athens witnessed some of the most violent protests in more than a year on Wednesday as demonstrators went on to the streets and took part in a general strike.
A confidence vote in the new cabinet is expected on Sunday, reports say.
"The discussions on the vote of confidence will begin on Sunday evening and will be completed by midnight on Tuesday," a parliamentary aide, who declined to be named, told Reuters news agency.
MPs' resignations
Mr Papandreou had also faced the threat of a revolt in his socialist Pasok party over the controversial package.
The EU leaders are at loggerheads over the issue: should Greece be allowed to do a soft, controlled, partial default on its debts which forces banks and pension funds to lose some of the money they lent to Greece?”
End QuotePaul MasonEconomics editor, BBC Newsnight
On Thursday, Greek government MP George Floridis resigned in protest at the austerity plan. He was followed shortly afterwards by Ektoras Nasiokas, another Socialist MP.
Earlier this week, another Socialist MP defected, leaving the party to sit as an independent.
The resignations do not affect the party's five-seat parliamentary majority as the seats are automatically allocated to the next Socialists in line, but they are an indication of the difficulties Mr Papandreou faces in winning confidence in his leadership, says the BBC's Malcolm Brabant in Athens.
The IMF is expected to pay the next tranche of Greek aid of 12bn euros ($17bn) on the basis of a promise of future EU funding rather than any concrete commitments.
This would give the EU more time to finalise a package to help Greece.
Assuming that some form of Greek government emerges out of the political discussions now under way in Athens, it is now almost certain that Greece will get the official money it needs to stay above water a few more weeks, notably the next tranche of last year's EU-IMF bailout, says the BBC's economics editor, Stephanie Flanders.
All the eurozone ministers have to do is agree in principle to fill the funding gap in the Greek economic programme, which they will now do on Sunday, adds our correspondent.
Eurozone finance ministers will decide on a new bailout in July, according to EU Economic and Monetary Affairs Commissioner Olli Rehn.
"I am confident that next Sunday, the Eurogroup will be able to decide on the disbursement of the fifth tranche of the loans for Greece in early July. And I trust that we will also be able to conclude the pending review, in agreement with the IMF," he said in a statement.
Such an approach "means that the funding of the Greek sovereign debt can now be ensured until September, while we take the decisions for the medium term, beyond September, in July", he added.
This is a critical month for Greece, our correspondent says. It has very little money left in its coffers and will literally run out of cash in July unless it receives the next tranche of money from the first bail-out which was agreed in May 2010.
'Road of duty'
Mr Papandreou, who came to power in 2009, has not indicated the extent of his ministerial shuffle, but correspondents say it may include the replacement of Finance Minister George Papaconstantinou.
Economic analysts predict the post is likely to be filled by Lucas Papademos, a former vice-president of the European Central Bank.
May 2010: EU and IMF agree bail-out package to prevent Greece defaulting on its debts; in return, Greece agrees to make 30bn euros of budget cuts over the next three years
February 2011: EU and IMF experts tell Greece it must make further cuts to keep its recovery on track
April 2011: EU figures reveal Greek deficit revised up to 10.5%, worse than previously thought
May 2011: Greece begins privatisation programme but is warned the IMF may not release more funds because Athens cannot guarantee it will remain solvent for the next 12 months
29 June 2011: Deadline for Greece to agree new austerity package
Greece's debt was downgraded by Standard & Poor's ratings agency earlier this week, making the debt the lowest-rated of the countrries it monitors.
On Wednesday, tens of thousands of activists and unionists gathered in Syntagma square in Athens, near parliament.
A further 20,000 people also demonstrated in Thessaloniki, police said.
The general strike was the third in Greece this year.
The events destabilised markets, with major indexes witnessing the biggest drop on Wednesday since 1 June, and the euro sliding more than 1% against the dollar.
Yields on Greece's 10-year bonds reached a record high of 18.4%.
Are you in Greece? What is your reaction to Mr Papandreou's proposal? Have you taken part in or witnessed the clashes? Send us your comments using the form below.
Send your pictures and videos to yourpics@bbc.co.uk or text them to 61124 (UK) or +44 7725 100 100 (International). If you have a large file you canupload here.
A powerful explosion has hit the Nigerian police headquarters in the capital, Abuja, officials say.
"The police force headquarters has been bombed, everywhere is bombed," deputy police spokesman Yemi Ajayi told AFP.
An emergency official said a suspected suicide bomber had died in the blast.
A Red Cross worker told Reuters other bodies were being evacuated from the scene, from where a large plume of smoke can been seen rising. No-one has claimed responsibility for the attack.
However, Islamist group Boko Haram has recently been targeting police and government officials.
The BBC's Jonah Fisher in Lagos says for the Nigerian authorities, the attack is an embarrassing strike at the very heart of their security establishment.
Officials say the explosion took place in the car park of the police headquarters.
"A suspected suicide bomber died in the incident. Many vehicles were destroyed," Yushau Shuaib, a spokesman for the National Emergency Management Agency told the AFP news agency.
Residents say the explosion was heard across the city.
Inauguration bombing
"My windows were shaking and I heard the loud noise. I saw smoke coming up," Reuters news agency quotes one witness as telling a local television station.
An eyewitness told the BBC Hausa Service that he heard two explosions and saw more than 30 dead bodies and about 40 vehicles destroyed.
A bus commuter who saw the blast told the BBC's Focus on Africa programme: "All of a sudden there was this loud explosion. Everybody was scared and people began to run around."
He said police and Red Cross officials had rushed to the scene, and had moved people away from the area.
"We are evacuating the dead bodies, it is too early for us to judge how many. Our priority is to treat the living casualties right now," a Red Cross spokesman told Reuters.
Most of Boko Haram's attacks have been in the northern city of Maiduguri.
But the group said it was behind a series of bombings that took place hours after President Goodluck Jonathan's inauguration last month.
On Tuesday, Nigeria's police chief promised to decisively deal with the group by sending more troops and equipment to the north, declaring they would be finished within a few months.
The group accuses Nigeria's government of being corrupted by Western ideas and wants to overthrow the state and impose Islamic law on the country.
It has killed dozens of people, mostly shot by gunmen riding motorbikes, in Maiduguri, the capital of Borno state.
Last year, officials blamed two explosions in Abuja during celebrations to mark the 50th anniversary of Nigeria's independence on militants from the oil-rich Niger Delta around Port Harcourt.
Are you in Abuja? Did you witness the attack? Send us your stories using the form below.
Send your pictures and videos to yourpics@bbc.co.uk or text them to 61124 (UK) or +44 7725 100 100 (International). If you have a large file you canupload here.
The long-serving second-in-command of al-Qaeda, Ayman al-Zawahiri, has been appointed its head following the death of Osama Bin Laden, the militant organisation said in a statement.
Bin Laden was killed by US forces in Pakistan in early May.
Al-Qaeda warned it would continue to fight a holy war against the US and Israel under Zawahiri's direction.
Analysts say Egyptian-born Zawahiri, 59, is intelligent but lacks the charisma of his predecessor.
He is claimed by some experts to have been the "operational brains" behind the 9/11 attacks on the US.
For years Bin Laden's deputy, with a $25m (£15m) bounty on his head, he had been widely anticipated to replace Bin Laden at the helm.
The statement announcing his appointment was posted on a militant website and attributed to al-Qaeda's General Command.
"Sheikh Dr Ayman al-Zawahiri, may God guide him, assumed responsibility as the group's amir [leader]", it said.
It vowed that under Zawahiri, it would pursue jihad or holy war against the US and Israel "until all invading armies leave the land of Islam".
'Jihadist renaissance'
Zawahiri, whose 60th birthday is believed to be this Sunday, warned just over a week ago that Bin Laden would continue to "terrify" the US from beyond the grave.
Dr Ayman al-Zawahiri was always going to be the default choice to succeed Osama Bin Laden.
A highly intelligent Egyptian extremist, he was the man who got Bin Laden to "think global" in the 1990s, broadening his message from just complaining about US troops on Saudi soil to a whole range of Muslim grievances from Kashmir to Palestine.
But experts say al-Zawahiri lacks the personal charisma of his predecessor. There are also doubts as to whether, as an Egyptian, he will command full authority over al-Qaeda's operatives from Saudi Arabia and other Gulf states.
In a video message posted on the internet on 8 June, Zawahiri said al-Qaeda would continue to fight.
"The sheikh has departed, may God have mercy on him, to his God as a martyr and we must continue on his path of jihad to expel the invaders from the land of Muslims and to purify it from injustice," Zawahiri said.
"Today, and thanks be to God, America is not facing an individual or a group, but a rebelling nation, which has awoken from its sleep in a jihadist renaissance."
The BBC's Middle East correspondent, Jon Leyne, says priorities for al-Qaeda's new leader may include attempting to to mount a big attack to show the organisation is still in business.
In addition, he says, Zawahiri will want to turn the wave of unrest in the Middle East to al-Qaeda's advantage - perhaps building more of a power base in Yemen and working to intensify the instability there.
Divisions?
In his message last week, Zawahiri applauded the Arab uprisings against "corrupt and tyrant leaders" and urged those involved to continue their "struggle until the fall of all corrupt regimes that the West has forced onto our countries".
But our correspondent adds that the delay in announcing Zawahiri as al-Qaeda chief - coming as it does more than six weeks after Bin Laden's death, despite his being the obvious choice - may point to divisions within the leadership.
Zawahiri has for years had a bounty on his head and security analysts have suggested he is most likely to be hiding in the Afghan-Pakistan border region.
However, Bin Laden and other key militant leaders who were also believed to be concealed there have instead been discovered in Pakistani towns and cities.
Bin Laden's killing by US special forces in a covert operation in the garrison town of Abbottabad on 2 May strained Washington's relations with Islamabad.
US President Barack Obama said "someone" was protecting Bin Laden, but Pakistan has denied any knowledge of Bin Laden's whereabouts and has arrested alleged CIA informants.
Greek PM George Papandreou has proposed a unity government as he tries to win support for austerity measures demanded by the EU and IMF, state TV reports.
Some reports said Mr Papandreou had even offered to step down, in talks with opposition leader Antonis Samaras.
Mr Papandreou has been facing the risk of a revolt in his Pasok party over the controversial austerity package.
Greek police clashed with protesters outside parliament over the measures, and unions held a general strike.
Mr Papandreou is seeking support for a new austerity programme of 28bn euros (£24.6bn; $40.5bn) in cuts to take effect from 2012 to 2015.
On Tuesday, one member of parliament defected from Mr Papandreou's Pasok party, leaving it with only 155 of the chamber's 300 seats.
At least one other Pasok deputy has threatened to vote against the new programme of cuts and privatisation of state assets, and a number of others are said to be wavering.
The EU and IMF are demanding the measures in return for the release of another 12bn euros in aid next month which Athens needs to pay off maturing debt.
Greek police have fired teargas at protesters outside parliament as MPs prepare to debate new austerity measures required for the EU and IMF bail-out package.
Demonstrators around Syntagma Square in Athens responded by throwing yoghurt and stones.
Thousands are taking part in a general strike, the third in Greece this year.
Ports, public transport and banks are badly disrupted as the main public- and private-sector unions go out on strike.
Prime Minister George Papandreou is seeking support for a new austerity programme of 28bn euros (£24.6bn; $40.5bn) in cuts to take effect from 2012 to 2015.
State-run companies have also joined the walkout, while hospitals are only offering emergency care. However, airports are operating normally after air traffic controllers called off their strike.
For all the leftist iconography plus the presence of that by now familiar demographic, the Facebook youth, or 'graduates with no future', this thing has gone beyond left and right - it's clear that for many people it is the Hellenic republic versus the rest of the world”
A top credit agency has cut Greece's rating, making it the least credit-worthy nation out of 131 countries it monitors.
The Greek government said the downgrade by Standard & Poor's - from B to CCC - ignored its efforts to secure funding.
In order for the next tranche of rescue loans to go through, parliament must adopt the new austerity plan by the end of June.
'Fight the battle'
Police thwarted protesters who were attempting to blockade parliament and stop MPs getting in for the debate.
They sealed off the roads leading to Syntagma Square and created a pathway for deputies.
The Greek demonstrators are calling themselves the "indignants", linking themselves to Spanish anti-austerity protesters who set up camps in Madrid and Barcelona.
The square is awash with Greek and Spanish flags, as well as banners reading "Resist" and the battle cry from the Spanish civil war, "No pasaran" (they shall not pass), the AFP news agency reports.
May 2010: EU and IMF agree bail-out package to prevent Greece defaulting on its debts; in return, Greece agrees to make 30bn euros of budget cuts over the next three years
February 2011: EU and IMF experts tell Greece it must make further cuts to keep its recovery on track
April 2011: EU figures reveal Greek deficit revised up to 10.5%, worse than previously thought
May 2011: Greece begins privatisation programme but is warned the IMF may not release more funds because Athens cannot guarantee it will remain solvent for the next 12 months
29 June 2011: Deadline for Greece to agree new austerity package
Mr Papandreou faces the risk of a revolt in his own Pasok party over the plans.
One MP defected from the party on Tuesday, leaving it with only 155 of the chamber's 300 seats.
"You have to be as cruel as a tiger to vote for these measures. I am not," George Lianis, a former sports minister, said in a letter to parliament's speaker announcing his departure from the parliamentary group.
At least one other Pasok MP has threatened to vote against the new programme of cuts and privatisation of state assets.
Another 14 MPs are wavering in their support for the austerity plan, our correspondent says.
Meanwhile, eurozone finance ministers have failed to agree on how to make private creditors contribute to a possible second Greek bail-out.
Ministers meeting in Brussels continued their discussions late into the night on Tuesday on ways of making private bondholders share the cost of a second rescue package without throwing financial markets into turmoil.
As a result of their failure to reach a deal, the cost of insuring Greek debt against default shot to an all-time high.
The Greek government has appealed for consensus over its proposals, which would see 6.5bn euros (£5.7bn; $9.4bn) in tax rises and spending cuts this year.
"Every Greek, particularly the new generation, demands that we fight the battle with all our power, a battle to avoid a disastrous bankruptcy which will undermine the future of the country," government spokesman George Petalotis told reporters.
"We are fighting the battle to serve the common good, in the most crucial moment in the country's modern democracy."
In a sign of possible contagion from the Greek crisis, credit rating agency Moody's said it might downgrade the three largest banks in France because of their exposure to Greek debt.
Share prices for BNP Paribas, Credit Agricole and Societe Generale all fell as a result.
France appealed for calm, saying it opposed a Greek restructuring which could entail write-offs for private banks.
"The French position is voluntary - no restructuring, no credit event and in line with the ECB," government spokesman Francois Baroin told reporters in Paris.
The EU and IMF are demanding the measures in return for the release of another 12bn euros in aid next month which Athens needs to pay off maturing debt.
Are you in Greece? What is your reaction to the latest general strike? Are you participating or is your business affected? Send us your comments and experiences using the form below.
Send your pictures and videos to yourpics@bbc.co.uk or text them to 61124 (UK) or +44 7725 100 100 (International). If you have a large file you canupload here.
Africa 
Are you in Syria? What is your reaction to events? Send us your comments using the forms below.