Updated at 6 p.m.
Deadly clashes over the weekend between Christian farmers and Muslim herders in central Nigeria have left at least 86 people dead and 50 homes burned to the ground, according to state police.
Herders from the north have been pushed south by climate change and also threats from terrorist group Boko Haram.
The herders' southward migration, into the savannah and rain forests of Nigeria's central and southern regions, has exacerbated religious and ethnic tensions.
Last Thursday, five herders of Muslim faith were attacked in a truck, their cattle taken and their vehicle torched, reported The New York Times. On Friday and Saturday night, suspected herders entered predominantly Christian villages, opening fire and burning homes while people were sleeping.
That incident triggered retaliatory measures in which Christian villagers set up blockades and killed motorists who they believed "looked" Muslim and Fulani — an ethnic minority group, Agence France-Presse reported.
Disputes between farmers and herders have cropped up over the years, largely because of fights over land and water use.
Some of Nigeria's Christian communities in the south also begrudge the influx of Muslim herders because they consider their arrival an "Islamisation force," the International Crisis Group stated in a 2017 report.
"In the absence of mutually accepted mediation mechanisms, these disagreement[s] increasingly turn violent," the organization said.
The report found that with a death toll of approximately 2,500 people in 2016, the conflict has become as violent as the Boko Haram insurgency in the northeast of Nigeria.
Nigerian President Muhammadu Buhari expressed regret over the weekend's killings. He vowed to apprehend the murderers.
"My deepest condolences to the affected communities," Buhari wrote from his official Twitter account. "We will not rest until all murderers and criminal elements and their sponsors are incapacitated and brought to justice."
Buhari also appealed for calm and said he supported Plateau State Governor Simon Bako Lalong and imposing a curfew throughout the region.
"The government has enforced a curfew from 6 p.m. to 6 a.m. in order to bring normalcy, (and) police and other security operatives have been put on alert at the moment," Plateau State's Commissioner of Information Yakubu Dati told Reuters.
In January, President Buhari tried to mitigate violence between the herders and farmers by deploying special forces to the central region.
He is using similar tactics following this weekend's bloodshed. He tweeted on Monday that the Chief of the Nigerian Armed Forces authorized the deployment of additional special forces to "beef up the strength of Operation Safe Haven (OPSH)."
The Nigerian president also added that Vice President Yemi Osinbajo is visiting Plateau State to assess the security situation.
In the meantime, state police told Agence France-Presse that the remains of people who were killed over the weekend have been released to their family members.