Roadblocks have been erected and overnight curfews implemented in the towns worst hit by the clashes.

President Umaru Yar'Adua, who is himself a Muslim from the north, has ordered security forces to take whatever action is necessary to restore order.

Police, who claim to have arrested almost 200 fighters, were searching homes and forests for militants around the affected towns.

Analysts say that while the group has caused chaos in the last few days, it is too early to say if it will emerge as a major threat to security in the impoverished north.

'Although this seemed spontaneous, it seemed that group had been building for a while and this was them testing their strength,' Elizabeth Donnelly, Africa Programme Manager at London-based think tank Chatham House, told DPA.

'At the moment they appear to be more of a fringe group than a real threat,' she added.

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 were also torched.

Hundreds died in the city of Jos, the capital of Plateau State, last November when local elections degenerated into bloody clashes.