Gunmen have killed 37 people in a pre-dawn raid in Nigeria's central Plateau state, the military has said.
Herdsmen from the Fulani ethnic group carried out the attack on villages inhabited mostly by the Berom community, a local organisation said.
Plateau state has been hit for years by inter-ethnic and religious violence, which has killed thousands.
It lies on the fault line between Nigeria's mainly Muslim north and mostly Christian and animist south.
Most Fulani are Muslim and Berom are Christians.
Military spokesman Salisu Mustapha said the gunmen opened fore on residents in four villages at around 0100 GMT.
"The attackers killed... 13 persons in Katu Kapang, eight in Daron, nine in Tul and seven others in Rawuru," he said, in a statement.
However, Fatima Njokwu, who works for the Stefanos Foundation, a Christian group in Nigeria, said three villages were raided.
Fulani herdsmen carried out the attack on the mainly Berom communities, she told the BBC Hausa Service.
The long-standing rivalries between communities stem from a dispute about who are the area's rightful inhabitants, tensions often whipped up by local politicians, correspondents say.