At least 40 people have died in clashes between an Islamist sect and police in northern Nigeria, reports said on Sunday.
Broadcaster Al-Jazeera reported that around 70 Nigerians wielding guns and hand grenades attacked a police station in Bauchi early Sunday morning.
The police repelled the attack. Some 42 people are believed to have died and dozens more have been injured, although it was not clear how many of the casualties were police officers.
Nigerian police claimed to have arrested over 100 fighters after the battle.
The fighters were part of Boko Haram, a group sometimes called the Nigerian Taliban, which wants to impose sharia, or Islamic law, across all of Nigeria.
Nigeria, Africa's most populous nation, is split between the Muslim north and the Christian and animist south.
The north has been gradually implementing stricter Islamic law, which has led to trouble with Christian groups.
Clashes in Bauchi earlier this year left five people dead and several churches and mosques gutted by fire.
Hundreds died in the city of Jos, the capital of Plateau State, last November when local elections degenerated into bloody clashes.