Violent protests erupted across Nigeria's largely Muslim north yesterday as youths angered at President Goodluck Jonathan's election victory torched churches and homes and set up burning barricades.
The vote count showed that Mr Jonathan, from the oil-producing Niger Delta, had beaten Muhammadu Buhari, a former military ruler from the north, in the first round, with around 57 per cent of votes to Buhari's 31 per cent.
Observers have called the poll the fairest in decades in Africa's most populous nation but Mr Buhari's supporters accuse the ruling party of rigging.
The results show how polarised the country is, with Buhari sweeping the north and Jonathan winning the largely Christian south. Jonathan had nearly 23 million votes to just over 12 million for Buhari.
The Nigerian Red Cross said churches, mosques and homes had been burned in rioting across the north and many people had been killed, but it was impossible to give a toll for now.
"In Kaduna we have seen dead bodies lying by the road," Red Cross official Umar Mairiga told Reuters. "Two thousand people have been displaced at one military camp alone."
Authorities in the northern state of Kaduna imposed a 24-hour curfew after protesters set fire to the residence of Vice President Namadi Sambo in the town of Zaria and forced their way into the central prison, releasing inmates.
The body of a small boy shot in the chest by a stray bullet was brought to a police station.
"They have destroyed our cars and our houses. I had to run for my life and I am now in my neighbour's house," said Dora Ogbebor, a resident of Zaria whose origins are in the south.
Plumes of smoke rose into the air in parts of Kaduna as protesters set fire to barricades of tyres. Security forces fired in the air and used teargas to disperse groups of youths shouting "We want Buhari, we want Buhari".
Police said the violence was political rather than ethnic or religious. Twelve years after the end of military rule, the army said it stood fully behind the government and democratic rule.
Jonathan appealed to all politicians to end violence.
"No one's political ambition is worth the blood of any Nigerian," he said in a statement.
Buhari was yet to make any public statement on the violence despite appeals by foreign embassies that he call for calm.