Nigerian security forces have killed 27 Muslim militants in a mountainous north-eastern region, officials say.
Police and soldiers have been hunting armed Islamists
Police and soldiers have been hunting armed Islamists who killed several people in Borno State on Monday.
Borno's police commissioner said five militants who had crossed into Cameroon would be returned to Nigeria.
The militants want to set up an Islamic government in Nigeria. Earlier this year they stormed police stations in Borno and neighbouring Yobe State.
On Monday three police officers and seven civilians were killed in two attacks by the militants - locally known as Taleban.
The attackers burned down the police stations and carried away large amounts of weapons and ammunition.
In January the group abducted 30 men in a village in Yobe, and attacked police stations in the region.
Afterwards one the released captives said the militants had tried to recruit him and were seeking to establish a new system of Sharia - or Islamic - law.
Sharia is practised in 12 states across Northern Nigeria, but it is not implemented fully.
Police say that at least one of the group's leaders had trained with the Taleban in Afghanistan.