Nigeria's acting president has ordered security forces to hunt down those behind an attack near the central city of Jos that left more than 200 people dead.
Al Jazeera's Yvonne Ndege, reporting from the capital Abuja, quoted police as saying that the attackers were Muslim Hausa-Fulani herders while the victims were mainly from the Borom community, a predominantly Christian ethnic group.
Villagers in Dogo Nahawa, located south of Jos in Nigeria's Plateau State, said the herders from nearby hills attacked the village at about 3am (02:00GMT) on Sunday, shooting into the air.
"The shooting was just meant to bring people from their houses and then when people came out they started cutting them with machetes," Peter Jang, a Dogo Nahawa villager, told the Reuters news agency.
'Roving bands of killers'
The office of Nigeria's acting president said Goodluck Jonathan had "directed that the security services undertake strategic initiatives to confront and defeat these roving bands of killers", who it blamed for "causing considerable death and injury".
Officials from the central government were holding an emergency meeting, she said, adding that there was now a heavy police presence in the area to prevent any reprisal attacks.
According to a Red Cross official, at least two other nearby communities were also targeted, in an area close to where sectarian clashes killed hundreds of people in January.
It was not immediately clear what triggered the latest unrest, but four days of sectarian clashes in January between mobs armed with guns, knives and machetes left hundreds of people dead in Jos, which lies at the crossroads of Nigeria's Muslim north and predominantly Christian south.
The tension appears rooted in resentment between indigenous, mostly Christian groups, and migrants and settlers from the Hausa-speaking Muslim north, all vying for control of fertile farmlands.
Patrick Wilmot, a sociologist and African affairs analyst based in London, told Al Jazeera that the problems in the area of Jos stem from a lack of economic development.
"People from all over Nigeria came and settled in the area. There was hardly any trouble in the area 15 or 20 years ago, but then the population has increased tremendously, [but] the resources have not increased.
"There is hardly any industry in the town. There is only one large factory. Most of the economy is based on commerce and farming and as a result of huge unemployment the people have become very attached to their religious and ethnic identities.
"The political leaders are irresponsible, they manipulate these fears of religious and ethnic differences and as a result it's a kind of tinderbox."