The UN has urged the authorities in Mozambique to investigate reports that militants massacred at least 50 villagers and beheaded women and children in the restive northern region of Carbo del Gado.
A statement from the organisation said Secretary General António Guterres was “shocked” by the reports.
In a recent attack, Islamist militants turned a football pitch in a village into an “execution ground”, where they decapitated and chopped bodies, other reports said.
The beheadings are the latest in a series of gruesome attacks that the militants have carried out in gas-rich Cabo Delgado province since 2017.
Up to 2,000 people have been killed and about 430,000 have been left homeless in the conflict in the mainly-Muslim province.
The militants are linked to the Islamic State (IS) group, giving it a foothold in southern Africa.
The group has exploited poverty and unemployment to recruit youth in their fight to establish Islamic rule in the area.
Many locals complain that they have benefited little from the province’s ruby and gas industries.
Rights group Amnesty International has accused Mozambican soldiers of committing atrocities during a crackdown on the violence, but the defence ministry dismissed the reports, saying militants regularly impersonated soldiers.