Residents and local officials say that more than 100 people have been killed in clashes between herders and farmers in Plateau, a state in the north-central part of Nigeria.

On Tuesday, armed men attacked villages and set fire to many houses in the Mangu area. At first, it was thought that about 20 people had died, mostly children and women.

Local herder Bello Yahaya said on Friday that the attack was a revenge for farmers killing a herder and his cows who had trespassed on their land last month.

Minista Daniel Daput, the chairman of Mangu local government, said that they had buried about 50 people in a mass grave. Residents said that they would bury another 50 people on Friday and they were searching for more people who were missing in the bush nearby.

Plateau is one of the many states in Nigeria’s Middle Belt that have diverse ethnic and religious groups. Hundreds of people have died in intercommunal violence in these states in recent years.

The conflict is often seen as a religious and ethnic one between Muslim herders who move around – mostly Fulani – and Indigenous farmers who are mostly Christian. But experts say that the conflict is also worsened by climate change and growing agriculture.

Makut Simon Macham, who speaks for Plateau’s governor, said that they were looking into the situation and would bring the suspects to justice, but he did not know how many people had died.