Those who died were reported to be mainly women and children
Survivors of violence in central Nigeria on Sunday have been telling the BBC what happened.
One witness in a village near the city of Jos said he heard his neighbours screaming as they were attacked.
Afterwards he saw the bodies of whole families, including women and babies, killed with machetes and burnt.
Another man said he had found his granddaughter hacked to death and said her killers spoke Fulani, a language used by Muslim nomadic herdsmen.
Correspondent Komla Dumor also visited a mass grave where more than 100 bodies from one village had been buried.
Earlier, Nigerian police revised the number of people they say were killed from more than 500 to 109.
The violence followed sectarian killings near Jos in January that left more than 300 dead, most of them believed to be Muslims.
Gabriel, the community leader in the village of Dogo Nahawa near the city of Jos, told the BBC his five-year-old granddaughter had been hacked to death with a machete.
He said the attack had started at about 0300 on Sunday. He said a group of Fulani-speaking men started shooting a heavy machine gun to scare the residents into the open, where they were cut down.
"The shooting was so heavy that people were afraid. People were running helter-skelter because of this.... They had never heard something like this before... People that were running and run into them, and they were macheted."
Another eyewitness, Pepi, initially heard gunshots and went with his wife to hide in the toilet.
"They want to break the door, the back door there, to get into the house because they said the Arna is inside - that's a peasant that has no religion... So then I tell my wife she should keep quiet. Then, they bring something to hit the door with, they hit the door because they said they should get into the house and kill the Arna. So I kept quiet."
He could hear his neighbours crying out, then there was silence. "Screaming, real screaming. Babies and the mothers all. Crying! Shouting! Later I hear no more."
When he came out of his house, he saw their burnt bodies bearing machete wounds.
"I went to my neighbour's house. I saw all the wives, they killed them, cut, cut their bodies. Put fire on them. And the babies. They killed all the children, almost four children there. They killed them with murders, put fire on them."
A spokesman for the Plateau State government, Gregory Yenlong, told the BBC that federal officials were to blame for security lapses.
"I can't understand [why] people are killed, people arrested, for such acts, and they are not being prosecuted. The Nigerian system, something's wrong with it.
"I can't understand [why] a governor of a state, who is enshrined in the constitution of the Federal Republic of Nigeria, is the chief security officer of the state - and yet cannot direct a police officer to arrest and prosecute a crime."