Christian leaders said 500-600 people were killed by Muslims in the northern Nigerian city of Kano in two days of rioting this week to avenge the slaying of hundreds of Muslims.
Reverend Andrew Ubah, general secretary of the Christian Association of Nigeria in Kano, said on Thursday he had records of almost 600 killed in three days of riots, many times more than the official police toll of 30.
"Almost 600 people have been killed and 12 churches burned," Ubah told Reuters, adding he was keeping a tally based on information from priests across Nigeria's second-largest city.
Witnesses spoke of gangs of Muslim youths armed with cutlasses and clubs hacking Christians and other outsiders to death in reprisal for the slaying of hundreds of Muslims by Christians in central Nigeria last week.
The violence subsided in many districts on Thursday although police barred access to suburbs where fighting was still raging.
A dusk-to-dawn curfew has been in force since Tuesday and authorities barred media access to hospitals and mortuaries.
David Emmanuel, a factory worker, said he saw two truck loads of bodies being driven along Kano streets on Wednesday night and counted at least 30 corpses in the street.
Two Reuters correspondents have seen another 35 bodies, most of them burned or mutilated with knives.
"Hundreds of people were killed," said Mark Amani, a leader of minority Christians originating from nearby Kaduna state.
"Some corpses were burned in wells. Even little children were killed. The bodies of pregnant women were ripped open and their bodies burned."
Thousands of Christians who fled their homes across the city took refuge in police barracks.
Nigerian authorities routinely underestimate death tolls from religious violence in the belief the true figures could spark reprisal attacks.
Heavy security was visible in other main cities across the oil exporting nation to prevent the violence spreading.
The government gave security forces in Kano the order to shoot rioters on sight on Wednesday, and a group of Muslims complained that police had shot innocent civilians.
The Kano riot erupted after hundreds of Muslims were killed by Christians in the remote farming town of Yelwa in central Nigeria 10 days ago.
Rival tribes of Christians and Muslims have been fighting tit-for-tat battles for control of the fertile farmland in Plateau state for three months, killing at least 350 people. But the scale of the conflict escalated last week when heavily armed Christians, who are in a majority in Plateau state, invaded Yelwa. Local Muslim leaders said they buried 630 bodies after the attack, but police spoke only of hundreds dead.
President Olusegun Obasanjo went to central Nigeria on Thursday to review the crisis. He argued in public with religious leaders in Plateau state when they questioned the government's will to resolve the crisis.