Nigerian villagers say Cameroonian troops pursuing Boko Haram extremists have fired rocket-propelled grenades indiscriminately that killed a family of four and have shot and killed two other civilians.

It's the latest of several reports accusing the military of neighboring Cameroon of killing scores of Nigerian civilians and razing villages in an apparent attempt to create a no-go zone along the border. Cameroon's government has denied previous similar charges, saying Nigerian and Cameroonian troops are deployed jointly in the area to fight Boko Haram.

Muhammad Abba, deputy commander of a civilian self-defense group, said relatives telephoned him Tuesday to describe how grenades exploded in the northeastern Ashigashiya village on Monday killing a family of four. Abba says the soldiers also dragged away two elderly men then shot and killed them.