A French policeman stands guard outside the headquarters of the satirical weekly Charlie Hebdo which published crude caricatures of the Prophet Muhammad in Paris on Wednesday. [Michel Euler / Associated Press]

A French magazine ridiculed the Prophet Muhammad on Wednesday by portraying him naked in cartoons, threatening to fuel the anger of Muslims around the world who are already incensed by a film in the United States mocking him.

The French government, which had urged the magazine not to print the images, said it was temporarily shutting down premises including embassies and schools in 20 countries on Friday, when protests sometimes break out after Muslim prayers.

Riot police were deployed to protect the Paris offices of satirical weekly Charlie Hebdo after it hit the news stands with a cover showing an Orthodox Jew pushing the turbaned figure of Muhammad in a wheelchair. On the inside pages, several caricatures of the Prophet show him naked.

Reacting to the publication, Essam Erian, acting head of the Egyptian Muslim Brotherhood's Freedom and Justice Party, told Reuters: "We reject and condemn the French cartoons that dishonor the Prophet and we condemn any action that defames the sacred according to people's beliefs."

Calling for a UN treaty against insulting religion, he added: "We condemn violence and say that peaceful protests are a right for everyone. I hope there will be a popular Western and French reaction condemning this."

Deja vu

Charlie Hebdo's website crashed on Wednesday after being bombarded with comments that ranged from hate mail to approbation.

The magazine is no stranger to controversy over issues relating to Islam.

Last year it published an edition "guest-edited" by the Prophet Muhammad that it called Sharia Hebdo. The magazine's offices in Paris were subsequently fire-bombed.

French government defended the right of magazine Charlie Hebdo to publish the cartoons.

French Prime Minister Jean-Marc Ayrault said anyone offended by cartoons could take the matter to the courts after expressing his "disapproval of all excesses".

But he emphasized France's tradition of free speech. "We are in a country where freedom of expression is guaranteed, including the freedom to caricature," he said on RTL radio.

"If people really feel offended in their beliefs and think there has been an infringement of the law - and we are in a state where laws must be totally respected - they can go to court," Ayrault said.

The controversial caricature was played off of the US-produced amateurish film The Innocence of Muslims, which has already set off violence in seven countries that has killed at least 28 people, including the US ambassador to Libya.