Hundreds of people are reported to have been killed in central Nigeria after Christians and Muslims clashed over the result of a local election.
A Muslim charity in the town of Jos says it collected more than 300 bodies, and fatalities are also expected among Christians.
There is no official confirmation yet, and figures are notoriously unreliable in Nigeria, says the BBC's Alex Last.
Police have imposed a 24-hour curfew and the army is patrolling the streets.
They have been given orders to shoot on sight in an effort to quell hostilities that mark the worst clashes in the restive West African nation since 2004.
For the second straight day on Saturday, angry mobs went through the town burning homes, churches and mosques.
The Nigerian Red Cross says at least 10,000 people have fled their homes.
The mostly Christian-backed governing party, the People's Democratic Party, was declared to have won the state elections in Plateau state, of which Jos is the capital city.
Security forces could be seen in the town
The result was contested by the opposition All Nigeria People's Party, which has support from Muslims.
Violence started on Thursday night as groups of angry youths burnt tyres on the roads over reports of election rigging.
Bodies from the Muslim Hausa community were brought into the central mosque compound.
The local imam, Sheikh Khalid Abubakar, said more than 300 dead bodies were brought there on Saturday alone.
Those killed in the Christian community would probably be taken to the city morgue, raising the possibility that the total death toll could be much higher.
Police spokesman Bala Kassim said there were "many dead," but couldn't cite a firm number.
Despite the overnight curfew, groups in some areas took to the streets again as soon as police patrols had passed by.
In 2001, more than 1,000 people died in religious clashes in the city, situated in Nigeria's fertile "middle belt" that separates the Muslim north from the predominantly Christian south.
And in 2004, a state of emergency was declared in Plateau state after more than 200 Muslims were killed in the town of Yelwa in attacks by Christian militia.
Correspondents say communal violence in Nigeria is complex, but it often boils down to competition for resources such as land between those that see themselves as indigenous versus the more recent settlers.
In Plateau, Christians are regarded as being indigenous and Hausa-speaking Muslims the settlers.
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