The attacks came in the night, as the villagers slept. Hundreds of Muslim herdsmen armed with guns and machetes swooped down on three Christian villages outside Jos in central Nigeria, killing more than 120 people early Sunday, according to witnesses.

There were contradictory reports on the casualties. Some said more than 120 were killed, while others put the number at about 200.

The massacre in volatile Plateau state -- long beset with ethnic-religious violence -- was apparently a revenge attack. Nomadic Fulani herdsmen had accused a group of local indigenous Christians -- Berom people -- of attacking their camp late last month, killing four people and stealing about 200 cattle.

In the latest violence, which appeared unrelated to national sectarian political frictions, hundreds of herdsmen launched coordinated attacks about 3 a.m. on three villages, Dogo Nahawa, Ratsat and Zot, about six miles south of Jos.

The herdsmen charged the villages, firing in the air, then cut down villagers as they fled their huts, witnesses said.

“Some people, whom we believed to be pastoralists, attacked three villages including our own with machetes, killing and burning people,” said Fidelis Tawkek of Dogo Nahawa in a phone interview. “They burned down most of the houses. They killed many women and children.

“They escaped after the attack. Up to this moment, houses are still burning and barns are smoldering.”

Jos and the surrounding areas had seen a series of violent attacks in January, which left more than 320 dead, police figures show.

Plateau state is on the dividing line between Nigeria’s predominantly Muslim north and the mainly Christian south, but the recurrent violent outbreaks have as much to do with bitter rivalry between the indigenous Christian Beroms and Muslim Hausas who came later, settling in Jos about a century ago.

The city lives on a knife’s edge, with friction between the Christians and Muslims who compete for jobs, business, land and resources. Similar tensions radiate throughout the state: Thousands have died in ethnic-religious violence in Plateau state in the last decade.

Sunday’s violence -- allegedly involving the nomadic Fulani herdsmen -- was slightly different. Because it was said to involve nomads, who reportedly fled after the attack, it was probably not related to the usual flare-ups resulting from the bitterness between the Christians and Hausa Muslims in the Jos area.

But the violence underscores the Muslim-Christian rivalry that permeates Nigerian political and economic life. The most recent example has been the bitter power struggle in the ruling People’s Democratic Party between southern Christians and northern Muslims over the presidency, following the illness of President Umaru Yar’Adua, a Muslim.

The country’s political stability hinges on a ruling party deal that the Muslim north and Christian south should rotate power: eight years to the north and eight to the south. The jostling over the presidency was resolved when the PDP affirmed that a Muslim northerner would rule until 2015.

On Sunday, acting President Goodluck Jonathan placed security forces in Plateau state on alert and ordered them to track and arrest the killers.

robyn.dixon@latimes.com

Times special correspondent Aminu Abubakar contributed to this report.