French satirical magazine Charlie Hebdo is selling out around France after appearing for the first time since Islamist gunmen massacred 12 people at its offices.

The front cover of the magazine - which will see three million copies printed - depicts the Prophet Mohammed holding a sign that says "Je suis Charlie" - a slogan taken up by supporters since the attack a week ago.

The edition's lead editorial said: "For the past week, Charlie, an athiest newspaper, has achieved more miracles than all the saints and prophets combined.

"The one we are most proud of is that you have in your hands the newspaper that we always made."

Profits from the "survivors' issue", which will be printed in French and Italian along with translations in English, Spanish and Arabic in electronic form,  will go to the families of victims of the shooting.

However, the cartoon has led to warnings from Muslim groups that it could "stir up hatred".

Al Azhar, Sunni Islam's most prestigious centre of learning based in Cairo, Egypt, said the drawings "do not serve the peaceful co-existence between peoples and hinders the integration of Muslims into European and Western societies."

French Muslim groups have also urged their communities to "stay calm and avoid emotive reactions" to the magazine.

Prime Minister Manuel Valls declared a "war against terrorism" on Tuesday and in a speech called for France to pull together after the attack and the killing of four hostages at a Jewish supermarket in Paris as well as the murder of a police officer in the capital.

He said: "France is at war against terrorism, jihadism, radicalism... (not) Islam and Muslims.

"I don't want Jews in this country to be scared, or Muslims to be ashamed."

Mr Valls called for France's intelligence and anti-terrorism laws to be strengthened and "clear failings" addressed.

The Charlie Hebdo gunmen - Said and Cherif Kouachi - and their accomplice, supermarket gunman Amedy Coulibaly, were known to French intelligence agencies and had been on a US terror watch list for some time.

The magazine had faced threats and was firebombed for featuring cartoons of the prophet.

It comes after new video emerged of the Kouachi brothers on the streets of the city after carrying out their attack on the Charlie Hebdo offices.

Funeral have taken place in Paris and Jerusalem for some of the 17 killed in the terror attacks, which included three police officers.

The head of Europol has warned up to 5,000 EU nationals pose a potential threat to Europe after travelling overseas to countries like Syria.