Protesters torched a church overnight in the southern Niger city of Maradi after the arrest of a prominent imam who was subsequently freed Sunday, religious and security sources said.
Sheikh Rayadoune, the imam of the Zaria mosque in Maradi, was detained Saturday after criticising a proposed law on religious worship as "anti-Islam" a day earlier.
He has appealed to his supporters to end the unrest.
The group behind the church attack also burned the pastor's car, a church official said in a WhatsApp message to parishioners that was copied to AFP.
A local security source confirmed the incident in Maradi's working-class district of Zaria.
Witnesses said that late Saturday youths set up roadblocks and burned tyres in the streets of Niger's third largest city as news of the imam's arrest spread.
More From This Section
A police source told AFP that Sheikh Rayadoune had been released Sunday afternoon, adding: "He has acknowledged his mistake and has apologised." Shortly before his release, the imam published a statement appealing for calm.
"All my supporters must stop burning things and making trouble in town: Islam does not recommend that, I have in no way been mistreated by police," the message said.
The imam said he had read a bad translation of the draft law, which had been transcribed from French into Hausa, Niger's main language. He added that he would rectify his position at Friday prayers.