Militants from a predominantly Christian tribe killed at least 500 people in two attacks on a Muslim town in central Nigeria, a senior Red Cross (search) official said Thursday.

Although an exact toll from the raids Sunday and Tuesday was unavailable, Red Cross workers who interviewed witnesses and families of victims, and inspected a mass burial site "estimate 500 to 600 dead," said Umar Abdu Mairiga (search), head of the Nigerian Red Cross team visiting the mostly Muslim town of Yelwa after the assaults by the Tarok tribe.

Thousands of people fled the fighting, and at least 158 people were wounded. About 100 people also were missing, many of them women and children allegedly abducted, Mairiga added.

Police, who tend to downplay casualty tolls to stem retaliatory attacks, earlier reported 80 killed, a figure repeated by the Nigerian Red Cross president Emmanuel Ijewere.

Religious, ethnic and political enmities — often intertwined — have fueled outbreaks of communal bloodshed resulting in more than 10,000 dead since President Olusegun Obasanjo was first elected in 1999, ending 15 years of repressive military rule.

Violence in central Nigeria has erupted in cycles since September 2001, when fighting between Christians and Muslims in the once-peaceful city of Jos killed more than 1,000 people. Hundreds more have been killed in fighting since then.

Few parts of Yelwa (search), a town of cattle herdsman and semi-nomadic traders, were left untouched in the latest raids; attackers with jerry cans of kerosene burned several mosques and hundreds, possibly thousands of homes and vehicles.

One charred corpse was still visible on the main street Thursday. Yakubu Haruna, a town councilor, estimated the toll would rise to 600 people, many of them buried by family members in fields and scrub forest surrounding the town.

On Wednesday, villagers showed an Associated Press reporter what they said was a burial site for 280 people killed in the raids — a 160-square-foot area of freshly upturned soil, located behind a mosque in a field smelling of decomposing bodies.

In Yelwa, the Red Cross provided medical treatment to 58 wounded, and at least 100 others were evacuated and treated in other locations, officials said.

In a makeshift clinic in front of the home of a local chief, Red Cross officials people injections of pain-relievers to men, women and children wounded with machete cuts and gunshot wounds.

Police escorted truckloads of other residents fleeing the town along a road through neighboring Shendam, a Christian Tarok community, saying they feared more fighting if they didn't accompany the groups.

Ambrose Nanlong, a 68-year-old community leader in Shendam, said some "Christian boys" from Shendam and nearby Kawo helped attack Yelwa to avenge what he called a raid by Muslim militants on Kawo.

That account could not be independently confirmed.

In February, Muslim militants in Yelwa were blamed for killing nearly 50 people, many of them Christians who took refuge in a church.