France is to close its embassies around the world on Friday, in case of a backlash against the publication of cartoons of the Prophet Mohammed.
The cartoons have just been published in satirical French magazine Charlie Hebdo in a move that is likely to inflame outrage among Muslims who have already been protesting against an anti-Islamic film.
At least 30 people have died so far in demonstrations against the Innocence of Muslims film in more than 20 countries.
The last time Charlie Hebdo stoked controversy over Islamic issues its Paris offices were fire-bombed.
That attack last year was blamed on an edition "guest-edited" by the Prophet Mohammed that it called Sharia Hebdo.
Charlie Hebdo's latest move was greeted with immediate calls from political and religious leaders for the media to act responsibly and avoid inflaming the current situation.
Prime Minister Jean-Marc Ayrault issued a statement expressing his "disapproval of all excesses".
The magazine's editor, originally a cartoonist who uses the name Charb, denied he was being deliberately provocative.
"The freedom of the press, is that a provocation?" he said. "I'm not asking strict Muslims to read Charlie Hebdo, just like I wouldn't go to a mosque to listen to speeches that go against everything I believe."
A protest in Yemen against the Innocence of Muslims film
Dalil Boubakeur, senior cleric at Paris's biggest mosque, called on France's four million Muslims to remain calm.
"It is with astonishment, sadness and concern that I have learned that this publication is risking increasing the current outrage across the Muslim world," he said.
"I would appeal to them not to pour oil on the fire."
France's Muslim Council also appealed for calm.
Meanwhile, France's leadership says it will not allow a planned protest on Saturday against the US-produced film Innocence Of Muslims to go ahead.
Messages on social networking sites had called for protests to be held in Paris, Marseille and other major cities.
But Mr Ayrault told French radio RTL: "There's no reason for us to let a conflict that doesn't concern France come into our country. We are a republic that has no intention of being intimidated by anyone."
France's Muslim community, most of whom have family links to north Africa, is the largest in western Europe.
The cartoons have just been published in satirical French magazine Charlie Hebdo in a move that is likely to inflame outrage among Muslims who have already been protesting against an anti-Islamic film.
At least 30 people have died so far in demonstrations against the Innocence of Muslims film in more than 20 countries.
The last time Charlie Hebdo stoked controversy over Islamic issues its Paris offices were fire-bombed.
That attack last year was blamed on an edition "guest-edited" by the Prophet Mohammed that it called Sharia Hebdo.
Charlie Hebdo's latest move was greeted with immediate calls from political and religious leaders for the media to act responsibly and avoid inflaming the current situation.
Prime Minister Jean-Marc Ayrault issued a statement expressing his "disapproval of all excesses".
The magazine's editor, originally a cartoonist who uses the name Charb, denied he was being deliberately provocative.
"The freedom of the press, is that a provocation?" he said. "I'm not asking strict Muslims to read Charlie Hebdo, just like I wouldn't go to a mosque to listen to speeches that go against everything I believe."
A protest in Yemen against the Innocence of Muslims film
Dalil Boubakeur, senior cleric at Paris's biggest mosque, called on France's four million Muslims to remain calm.
"It is with astonishment, sadness and concern that I have learned that this publication is risking increasing the current outrage across the Muslim world," he said.
"I would appeal to them not to pour oil on the fire."
France's Muslim Council also appealed for calm.
Meanwhile, France's leadership says it will not allow a planned protest on Saturday against the US-produced film Innocence Of Muslims to go ahead.
Messages on social networking sites had called for protests to be held in Paris, Marseille and other major cities.
But Mr Ayrault told French radio RTL: "There's no reason for us to let a conflict that doesn't concern France come into our country. We are a republic that has no intention of being intimidated by anyone."
France's Muslim community, most of whom have family links to north Africa, is the largest in western Europe.