At least 10 people have been killed and 45 churches set on fire since protests erupted in Niger over the French magazine Charlie Hebdo’s depiction of the Prophet Muhammad, police say.
The government has declared three days of mourning for those who died.
Hotels and bars were also burned to the ground during a weekend of violent protests, the authorities said.
Islamist gunmen killed 12 people at Charlie Hebdo’s offices in an attack earlier this month.
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”.
It led to criticism from many living in Muslim-majority countries who said the magazine’s editors were being unnecessarily provocative.
Niger’s interior minister said that some of those taking part in the weekend protests held up flags supporting Boko Haram, an Islamist group based in neighbouring Nigeria.
But the BBC’s Bashir Saad Abdullahi in Niger says political friction is also likely to have played a role in fanning the violence.
In the capital Niamey at least five people were killed during the clashes, while another five died in the southern city of Zinder.
More than 170 people were injured, officials said.