Forty-five churches were torched over the weekend in Niger's capital during deadly protests over the publication of a Prophet Mohammed cartoon by the French satirical weekly Charlie Hebdo, police say.

The protests, which left five people dead and 128 people injured in Niamey, also saw a Christian school and orphanage set alight, said Adily Toro, a spokesman for the national police.

Similar unrest sparked by the French satirical publication, which was targeted by a bloody Islamist raid on January 7, saw five people killed, 45 wounded and the French cultural centre burned in the southern city of Zinder.

"The French flag was burned," Mr Toro said, adding that 189 people, including two minors, were arrested by police.

Demonstrators also pillaged and burned numerous premises, including five hotels and 36 bars.

France's president Francois Hollande said last week anti-Charlie Hebdo protesters in other countries did not understand his country's attachment to freedom of speech.

In the attack on Charlie Hebdo, gunmen killed 12 people, saying they were avenging previous publications of cartoons depicting the prophet.

A week later staff defiantly produced a "survivors' issue" with a new cartoon, winning backing from vocal supporters of freedom of expression, but further provoking Muslims in a number of countries.

On Sunday, some 300 protestors in Niamey defied a ban on further demonstrations, throwing stones at police who fired tear gas at them.

The governor of the capital, Hamidou Garba, said 90 people were arrested.

Muslim elder Yaou Sonna urged people to stop attacking Christians.

"Don't forget that Islam is against violence," he said on state television.

"I urge men and women, boys and girls, to calm down."

Many Muslims, who form an overwhelming majority of Niger's population, see any depiction of Islam's prophet as offensive.

Government officials said 800,000 people rallied in the Chechen capital Grozny. ( AFP: Yelena Fitkulina )

Chechnya protesters vow to 'punish' those who insult Islam

In similar demonstrations, hundreds of thousands of people rallied in Grozny, the capital of Russia's Muslim North Caucasus region of Chechnya, to protest against the cartoons.

An AFP journalist at the event put the attendance figure at several hundred thousand, while authorities in the tightly controlled region said more than one million people — almost the entire population of the republic — took part in the rally.

Ramzan Kadyrov, who has ruled Chechnya with an iron fist since being installed by president Vladimir Putin a decade ago, addressed the rally.

"This is a protest against those who support the publication of caricatures of the Prophet Mohammed," he said.

The leader attacked the French government for backing Charlie Hebdo magazine's right to run a cartoon of Prophet Mohammed on its front cover days after the Islamist attack.

"We say firmly that we will never allow anyone to go unpunished for insulting the name of the Prophet and our religion," Mr Kadyrov said.

Demonstrators chanted "Allahu Akbar" (God is greatest) and released balloons into the sky at the highly choreographed event, as speakers harangued Western governments' argument that printing caricatures of Islam's prophet was a matter of free speech.

Authorities in Chechnya, which has a total population of about 1.25 million, said they had expected some 500,000 people to attend the rally and appealed for believers to come from around the North Caucasus region.

Human rights activists said crowds were often boosted by large numbers of students and workers ordered to attend by state-run institutions and managers.

Although Russia's leadership extended its condolences to France, and foreign minister Sergei Lavrov participated in a unity march held in Paris following the attacks, pro-Kremlin commentators and Muslims accused the cartoonists of provoking the attack.

Protests call for diplomatic ties to be cut

Meanwhile, hundreds of people in Afghanistan, Iran, Pakistan and Gaza demonstrated against Charlie Hebdo, burnt French flags and called for diplomatic ties with France to be cut.

Demonstrators in the eastern Afghan city of Jalalabad chanted anti-France slogans and vowed to defend Islam.

"I call on the Afghan government and other Islamic countries to cut off their diplomatic ties with France," 25-year-old protester Matiullah Ahmadzai said.

"We want the French embassy in Kabul closed. France should apologise to Muslim countries."

In neighbouring Pakistan, five protests were held in the north-western city of Peshawar and one in the southern port city of Karachi.

More than 2,000 Iranians protested outside the French embassy in Tehran, chanting "Death to France", with female protesters segregated from the males.

In Gaza, about 200 supporters of the Islamic State group staged a rally outside a French cultural centre.

The protesters, members of the hardline Salafi movement, brandished black jihadi banners and threatened attacks against France.

"French, leave Gaza or we will slaughter you," the crowd chanted in front of the French cultural centre.

AFP