Unidentified assailants killed two customs officers, a policeman and a civilian in an overnight attack on a security post in northern Cameroon, the mayor and two military sources said on Tuesday.
The attack took place at the entrance to the town of Mora in Cameroon's Far North region, about 30 km (20 miles) from the border with Nigeria.
One of the military sources, who requested not to be identified, attributed it to the Islamist Boko Haram, which is waging an insurgency in the region.
