"We have been able to make 95 arrests but at the same time over 500 people have been killed in this heinous act... by Fulani herdsmen," Dan Manjang said in a telephone interview.
The Nigerian army was on alert on Monday after Muslim herdsmen raided a Christian village near the restive city of Jos, hacking to death over 200 people.
Witnesses in the village of Dogo Nahawa told Nigeria's Vanguard newspaper that Hausa-Fulani tribesmen descended from the hills, firing shots in the air. When people ran out of their homes, they were set upon with machetes or shot.
Outbreaks of violence are common in Plateau State, where the indigenous Christians have long struggled with immigrant Muslims over resources. Over 300 hundred died in January, when rival gangs of youths clashed in Jos.
Act of jihad
A local Christian group said on Sunday the latest violence was an act of jihad.
"The attack, yet another jihad and provocation of the Christians, started at about 1.30 am last night," Plateau State Christian Elders Consultative Forum said in a statement.
"Eye-witnesses say the Hausa-Fulani Muslim militants came chanting 'allahu akbar' and broke into homes, cutting human beings, including children and women, with their knives and cutlasses," the statement added.
Acting President Goodluck Jonathan has put the army on alert in the region, but the Christian group said it had lost faith in the military, which it says failed to respond until the attack was over.
The massacre was believed to be in reprisal for the violence in Jos at the start of the year.