Anger over the result of Nigeria’s presidential election triggered riots that killed several people in the north of the country, the homeland of the runner-up.
Gangs of youths torched churches, houses and vehicles in Kaduna state and Kano where authorities had to impose a curfew.
The Red Cross could not put an exact figure on the number of dead, but said nearly 300 were injured and 15,000 had to flee the violence.
Supporters of the loser, Muhammadu Buhari, claimed the ruling party had rigged the election, and refused to recognise the result.
Official figures showed that sitting president, Goodluck Jonathan, polled nearly 23 million votes, against his opponent’s 12 million plus.
Jonathan, who comes from the south of Nigeria, appealed for an end to the violence.
Buhari’s party wrote to the electoral commission alleging voter intimidation and ballot-box stuffing in the president’s strongholds.
EU monitors said it was the fairest election in Nigeria for decades.