The head of the French Muslim Council (CFCM) has condemned the deadly shooting on a popular satirical newspaper by three suspected Islamic extremists, calling it a "declaration of war".
"It's a thunderous declaration of war," Mr Dalil Boubakeur, who is also imam of the mosque of Paris, was quoted as saying by Le Figaro newspaper.
"The times have changed. We're entering a new phase of this confrontation," he said. He added that "we are horrified by the brutality and the savagery" of the attack on Charlie Hebdo, which killed at least 12 people, including the newspaper's editor-in-chief and its top cartoonists.
"We absolutely condemn such an act and we look forward to the authorities meting out justice," said Mr Boubakeur, who planned to visit the scene of the shooting, according to his entourage.
"The (Muslim) community is dumbfounded by what has happened."
The CFCM represents France's Muslim community, which is Europe's biggest and estimated to number between 3.5 million and five million people.
The council said in a statement as reported by Agence France-Presse: "This extremely grave barbaric action is also an attack against democracy and the freedom of the press."
The Muslim council also called for calm and urged Muslims to beware of extremist manipulation. "In this tense international climate stoked by the madness of terrorist groups unjustly claiming to represent Islam, we call on all those attached to the republic's values and to democracy to avoid provocation", it said.
The Muslim community must practise "the greatest vigilance towards possible manipulation by extremist groups," it added.
Another imam of the greater Paris region also expressed his outrage. "I am extremely angry. These are criminals, barbarians. They have sold their soul to hell. This is not freedom. This is not Islam and I hope the french will come out united at the end of this," Mr Hassen Chalghoumi, imam of the Drancy mosque in Paris's Seine-Saint-Denis northern suburb, was quoted by Reuters as saying.
A separate statement from an organisation close to the Muslim Brotherhood, the Union of French Islamic Organisations (UOIF), also condemned "in the firmest manner this criminal attack and these horrible murders", AFP reported.
The Great Rabbi of France, Haim Korsia, told AFP that the country needed to show "national unity and defend all together our freedoms, including the freedom of expression." France also has Europe's biggest Jewish population of between 500,000 to 600,000.