At least four people have been killed in violent protests against French magazine Charlie Hebdo in Niger's second city of Zinder, officials say.
A number of churches and the French cultural centre were among several buildings raided and set alight.
Friday saw protests across the Muslim world over the magazine's publication of a cartoon of the Prophet Muhammad.
It comes more than a week after gunmen carried out a massacre at the French magazine's offices in Paris.
Twelve people were killed in the attack.
The cover of the magazine's latest edition, published after the attack, featured a cartoon of the Prophet Muhammad weeping while holding a sign saying "I am Charlie".
Protests against the magazine were also seen on Friday in Pakistan, where protests turned violent in Karachi, the Sudanese capital of Khartoum and the Algerian capital, Algiers.
'Charlie is Satan'
One policeman and three civilians were killed in the protests in Zinder after Friday prayers, a police source told Reuters.
"Some of the protesters were armed with bows and arrows as well as clubs. The clashes were very violent in some places," the source added.
Agence France-Presse quoted a minister as saying dozens of people had been injured.
Local residents told Reuters that demonstrators had set fire to churches and raided shops that were run by Christians.
"The protesters are crying out in local Hausa language: Charlie is Satan - let hell engulf those supporting Charlie," a local shopkeeper said by telephone.
The French cultural centre there also came under attack.
The centre's director, Kaoumi Bawa, said an angry crowd of around 50 people had smashed the building's door and set fire to the cafeteria, library and offices.