Community leaders in central Nigeria have accused government troops of killing dozens of civilians and burning villages following the deaths of six soldiers at the hands of tribesmen.
Residents of Wase district in Plateau state said troops arrived on Saturday night and opened fire indiscriminately.
The army denies killing civilians but a spokesman said one of its units had engaged a local militia group.
The group is not connected to the Islamist militants Boko Haram.
Last week six soldiers were killed and mutilated by tribesmen – reportedly members of the Tarok tribe – who were allegedly involved in cattle rustling.
Plateau state has witnessed violence blamed on land disputes between semi-nomadic herdsmen and farmers.
Addressing a news conference in the Plateau state capital, Jos, community leader Comrade Jangle Lohbut said he had documented at least 38 deaths at the hands of troops.
“Soldiers stormed some villages in Wase. Villages belonging to Tarok and other tribes were razed and many lives, men, women and children, were lost,” he said.
Local traditional ruler Chief Jessie Miri said he believed that up to 80 people had been killed.
Military spokesman Captain Ikedichi Iweha denied soldiers had targeted civilians, saying that troops were battling militiamen in the area.
“Yesterday, contact was made with the militia group and a firefight ensued. It is still going on,” he said.
Last year, Amnesty International accused the Nigerian army of committing atrocities in the north-east in its fight against Boko Haram.
The military said it would investigate any alleged attacks on civilians.