Paris:
France was braced for a backlash on Wednesday as a satirical weekly magazine that published cartoons featuring crude depictions of the Prophet Mohammed flew off the shelves.
Embassies, consulates, cultural centres and international French schools in around 20 Muslim countries will be closed on Friday for fear of violence following weekly prayers.
Tempers are already running high in the Muslim world with over 30 people having been killed since protests began last week over the anti-Islam film "Innocence of Muslims."
Riot police were deployed outside the Paris offices of Charlie Hebdo, the satirical magazine which published the cartoons.
In the multi-cultural district of Belleville, angry Muslims queued up before dawn at news-stands in order to obtain copies of the weekly in order to rip them up.
That helped ensure the weekly's usual print run of 75,000 copies was sold out by mid-afternoon and defiant editor Stephane Charbonnier announced that extra copies would be printed to keep up with demand.
The left-wing, libertarian weekly enjoyed record sales of 400,000 copies in 2006 when it reproduced controversial Danish cartoons of Mohammed.
Last year it published an edition "guest-edited by Mohammed" that it called Sharia Hebdo, provoking a fire-bomb attack on its offices.
In the first significant reaction to Wednesday's edition, the magazine's website was put out of action by a cyber-attack that police were investigating.
Prime Minister Jean-Marc Ayrault said anyone upset by the caricatures could sue but he backed the weekly's right to offend.
"We are in a country where freedom of expression is guaranteed, including the freedom to caricature," he said.
"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."
A complaint of incitement to hatred was lodged by a Syrian organisation with a Paris prosecutor on Wednesday but there was no immediate decision on whether there would be criminal proceedings.
Leaders of France's four million Muslims said an appeal for calm would be read out in mosques across the country on Friday but also condemned the magazine for publishing "insulting" images.
The weekly carried a total of four cartoons which include images definitely intended to represent Mohammed, as opposed to any other Muslim.
In two of them, the Prophet is shown naked.
One is inspired by Jean-Luc Godard's 1963 film "Contempt" and features Mohammed asking the director "You like my buttocks?" -- echoing a line delivered by Brigitte Bardot in the film.
Another shows the founder of Islam crouched on all fours with a star coming out of his behind with the inscription "A Star Is Born."
The film references were intended to satirise the crudely-made short movie which has triggered the worldwide protests.
But the explicit nature of the drawings made it inevitable they would cause offence. Many Muslims regard any depiction of the Prophet as blasphemous.
France banned all protests over the controversial film following a violent demonstration last weekend near the US embassy and Interior Minister Manuel Valls said Wednesday he would not allow protests over the cartoons either.
Charlie Hebdo's editor, Stephane Charbonnier, described those getting irate over the cartoons as "ridiculous clowns" and accused the government of pandering to them by criticising him for being provocative.
"It is like saying a woman who has been raped is to blame because she wore a mini-skirt. We are provocateurs, we are wearing a mini-skirt but who is guilty: the person in the mini-skirt or the rapist."