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.