A Moroccan man was stabbed to death in his own home in southern France in what a Muslim group called a "horrible Islamophobic" attack the week after France was rocked by the Charlie Hebdo killings.

The 28-year-old attacker forced the front door of his neighbors' house in the picturesque village of Beaucet near Avignon just after midnight on Wednesday shouting "I am your god, I am your Islam" before repeatedly stabbing Mohamed El Makouli,  he National Observatory Against Islamophobia said Friday.

Thousands of people took to the streets of Nouakchott on Friday to  protest against a cartoon of the prophet Mohammed published in the latest edition of the French Charlie Hebdo weekly.

The protesters set fire to a French flag but were prevented by security forces from reaching the French embassy in the Mauritanian capital, witnesses said.

Around one hundred protesters turned out Friday for a rally in a conservative Istanbul district to support the two brothers who gunned down 12 people in an attack on French satirical weekly Charlie Hebdo.

Responding to an appeal by a group calling itself the Fraternal Platform of the Prophet's Companions, the demonstrators held up a banner with the pictures of Cherif and Said Kouachi as well as the late al-Qaida chief Osama bin Laden.

U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif met in Paris on Friday to discuss negotiations for a nuclear deal, a U.S. official said.

The pair, who held a marathon six-hour round of talks in Geneva earlier this week in a bid to nail down a deal, were taking the opportunity to meet again in the French capital on separate diplomatic trips.

Turkish President Recep Tayyip Erdogan on Friday lashed out at Charlie Hebdo for its "provocative" publications about Islam, saying the French satirical weekly incited hatred and racism.

"This magazine (is) notorious for its provocative publications about Muslims, about Christians, about everyone," Erdogan told a meeting of businessmen in Ankara.

In the aftermath of France's jihadist attacks, many have been left scratching their heads over how authorities can vaunt the importance of free speech while jailing people for comments that appear to "condone terrorism".

The deadly attacks also brought to the fore the contested right to mock religions in a country with a large Muslim community, after the Charlie Hebdo satirical magazine was targeted for its past depictions of Prophet Mohammed, viewed as highly offensive under Islam.

Hundreds of people lined up before daybreak in London on Friday to buy copies of French magazine Charlie Hebdo, but those hoping to get an English copy were disappointed as newsagents awaited delivery.

Around 200 people queued up in South Kensington, home to much of London's large French community, outside two French bookshops both stocking the latest edition of the magazine that was the focus of last Wednesday's deadly terror attack in Paris.

Secretary of State John Kerry clasped French President Francois Hollande in a warm embrace Friday and said the U.S. shared France's pain after its deadliest attack in half a century.

In an unusual move, Hollande trotted down the steps of the Elysee Palace to greet Kerry, who hugged the French president in front of a phalanx of photographers.

Niger Thursday banned distribution of Charlie Hebdo in the mainly Muslim country, with the government "vehemently" condemning the cartoon of the Prophet Mohammed in the latest issue of the French satirical weekly.

"The government vehemently denounces and condemns the cartoon of the Prophet Mohammed, peace and blessings be upon him, contained in the issue of Charlie Hebdo for Wednesday, January 14, 2015, which it considers an insulting provocation and totally unacceptable," it said in a statement read on radio and state television.

U.S. Secretary of State John Kerry arrived in France Thursday "to share a big hug for Paris" hours after funerals were held for five of the 17 people killed in last week's jihadist attacks.

Seeking to put behind a furore over the absence of a senior U.S. official at a mass Paris rally in the wake of the shootings, Kerry touched down just as an anti-terrorism operation was underway in neighboring Belgium, leaving two suspects dead.