Six soldiers of the Nigerian army were ambushed and killed by gunmen while on patrol in the northern Niger state on Friday, the army said, the latest loss inflicted on the military by armed criminal gangs.

Beyond fighting Islamist militants in the northeast, Nigeria's military has been called upon to tackle the threat in northern and central regions posed by criminal gangs who kill and kidnap villagers and schoolchildren.

Nigerian Army spokesperson Major General Onyema Nwachukwu said in a statement late on Sunday that troops of the 1st Division were on a fighting patrol in Karaga village in Niger's Shiroro local government area when they were ambushed.

Largely rural Shiroro is an area of Niger state where armed gangs, known locally as bandits, frequently attack villages and security personnel.

Nwachukwu said the troops were pursuing gunmen who had escaped after other members of the gang were killed by soldiers and their equipment captured.