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.

The results show how polarized 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 burned 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.