KANO, Nigeria (Reuters) - Nigerian President Goodluck Jonathan appealed for unity on Monday after deadly riots erupted in largely Muslim opposition strongholds over his election victory.
Churches, homes and shops were set ablaze and the Red Cross said many people were killed, hundreds injured and thousands displaced in the outburst of anger by supporters of Jonathan's northern rival, former army ruler Muhammadu Buhari.
"We must quickly move away from partisan battlegrounds," Jonathan said in his acceptance speech after being declared the winner with 57 percent of the vote to Buhari's 31 percent.
"Nobody's political ambition is worth the blood of any Nigerian," said Jonathan, the first president from the Niger Delta region which accounts for most of Nigeria's oil wealth.
Observers have called the poll the fairest in decades in Africa's most populous nation. But Buhari's supporters accuse the ruling party of rigging and rejected the results.
The results show how polarised the country of 150 million is, with Buhari, 68, sweeping the north and Jonathan, 53, winning the largely Christian south.
The Nigerian Red Cross said churches, mosques and homes had been burnt in rioting across the north and many people had been killed, but it was impossible to give a toll for now. It said nearly 300 people had been injured and 15,000 displaced.
"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 five states imposed curfews. Protesters set fire to the residence of Vice President Namadi Sambo in the town of Zaria. 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.
Buhari was yet to make any public statement on the violence despite appeals by foreign embassies that he call for calm.
The former general's Congress for Progressive Change (CPC) party said in a letter to the electoral commission that voters had been intimidated, ballot boxes stuffed in Jonathan's strongholds and computers set up to deprive it of votes.
"What is being exhibited to the world is not collated from polling units but from the state headquarters where a lot of manipulations, we believe, had taken place," the party said.
None of the opposition parties signed acceptance of final results issued by the Independent National Electoral Commission, an indication of potential legal challenges to come.
Nigeria has a history of rigged and violent elections but Saturday's vote was deemed by many Nigerians, and foreign observers, to have been a vast improvement on the past.
"Election day showed a generally peaceful and orderly process," said chief European Union election observer Alojz Peterle. EU observers said 2007 elections were not credible.
The independent Swift Count monitor group said the official results were right in line with what they would have expected based on their samples from a random selection of nearly 1,500 of the 120,000 polling stations across Nigeria.
The outright win for Jonathan could ease worries over potential disruptions to crude exports from Africa's biggest oil and gas industry -- far away from the disturbances in the north.
It could also lift local financial markets which had been unnerved by the prospect of a potential run-off. The All-Share Index closed up 2.3 percent to its highest in nearly a month.
"We will see a lot of investors come back to Nigeria," said Alan Cameron, London-based economist of stockbroker CSL.
The troubles in the north, on the fringes of the Sahara desert, are far from the oil-producing regions and heaving industrial centres of the south.
Members of Jonathan's family threw a party for thousands of supporters near his home village of Otuoke, attended by youths, traditional elders and dignitaries including a star from the local Nollywood film industry.
"The president is from this area so there is no way he will not make things happen for his people," said Peter Okoba, a former militant fighter who accepted a 2009 amnesty brokered by Jonathan to end Niger Delta unrest. "There's no way he can leave his people behind."
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(Additional reporting by Mike Oboh in Kano, Sahabi Yahaya and Joe Bavier in Kaduna, Austin Ekeinde in Port Harcourt, Chijioke Ohuocha in Lagos, Joseph Penney in Yenagoa; Writing by Nick Tattersall; Editing by Matthew Tostevin)