At least 86 people have died in central Nigeria after violent clashes broke out between farmers and cattle herders, police in Plateau state said.
Some reports say fighting began on Thursday when ethnic Berom farmers attacked Fulani herders, killing five of them.
A retaliatory attack on Saturday led to more deaths.
The area has a decades-long history of violence between ethnic groups competing for land.
Earlier, dozens of people were killed in a similar round of violence between Fulani herders and local hunters in Mali.
A curfew has now been imposed in three parts of Plateau state.
State police commissioner Undie Adie said a search of villages following the bloodshed revealed that 86 people had been killed, and six injured.
He said 50 houses had been burned, as well as 15 motorbikes and two vehicles.
The Plateau state government said the curfew would be in place between 18:00 and 06:00 local time (17:00 to 05:00 GMT) in the Riyom, Barikin Ladi and Jos South areas "to avert a breakdown of law and order".
The state's governor Simon Lalong said work was under way "to secure the affected communities and fish out perpetrators of these crimes".
"While we pray for God's guidance through this difficult time, we will do everything humanly possible to secure our state immediately," he said.
Nigeria's President Muhammadu Buhari - himself a Fulani - is under increasing pressure to address the tensions ahead of elections in 2019.
In January he ordered the head of police to relocate to the country's middle belt to manage clashes there.
Special forces were also deployed to the central states of Benue, Nasarawa and Taraba to "secure vulnerable communities and prevent further attacks".