Authorities said there has been an explosion in northern Nigeria where dozens are reported to have been killed this week in post-election violence.
Security sources said the blast on Friday evening hit in the city of Kaduna, the capital of the state of the same name. Reuters news agency says at least two people were killed as they accidentally detonated a bomb they were trying to assemble.
Riots broke out in the predominantly Muslim north this week after incumbent President Goodluck Jonathan, a Christian from the south, won Saturday's election. Muslim supporters of his unsuccessful challenger in the race, Muhammadu Buhari, have attacked churches, homes, and police stations. The violence has sparked counterattacks by Christians.
Media reports say more than 100 people were killed in the violence, though officials have declined to give a death toll for fear of prompting more attacks.
Officials have postponed gubernatorial elections in Kaduna and nearby Bauchi states until Thursday, to allow "the further cooling of tempers."
The organization Human Rights Watch has called on Nigerian leaders to make sure security forces act responsibly in stopping the post-election violence.
Jonathan is sending additional security forces to the area. But Human Rights Watch researcher Eric Guttschuss told VOA that Nigerian security forces have a history of abuse and excessive use of force when responding to sectarian clashes.
He said those forces should make sure they provide security in a neutral manner for citizens in those areas.
Some information for this report was provided by AFP and Reuters.