A witness says as many as 10 people have been killed when security forces clashed with Shiite Muslims attending a religious ceremony in northern Nigeria.

Mallam Hussaini says police and soldiers opened fire on Shiites who had gathered Wednesday in Funtua, Katsina state, for Ashoura, a holiday marking the martyrdom of the Prophet Muhammad's grandson.

Katsina police spokesman Salisu Abubakar Agaisa says he cannot confirm any deaths. He says local officials had banned Ashoura gatherings.

Nigeria is almost equally divided between Christians and Muslims, most of them Sunni. Tensions with the Shiite population are high after the army gunned down more than 300 people in an attack last December on the headquarters of a Shiite group in Kaduna state.