The Democratic Republic of Congo is scheduled to release the final results of last week's presidential election amid threats of violence from supporters of the top candidates.

The country's election commission was supposed to give the results on Tuesday, but announced a 48-hour delay.

Preliminary results from nearly 90 percent of polling places showed incumbent President Joseph Kabila was likely headed for re-election with almost 50 percent of the vote. His closest challenger, Etienne Tshisekedi had 33 percent.

The capital, Kinshasa, has been largely calm, but supporters of both men have hinted that violence could break out if their candidate is not named the winner.

Troops are on standby in case of unrest, while the United Nations, European Union and African Union have called on civilians and political figures to remain calm and avoid bloodshed.

Last week's balloting was only the second free election since the African nation was torn apart by several years of warfare that ended in 2003.

Voting was supposed to last for one day but stretched into three because of ballot shortages and scattered incidents of violence.

The delay in releasing results means Mr. Kabila has remained in office past the end of his term, which expired at midnight Tuesday.

Human Rights Watch says at least 18 people were killed in violence leading up to the vote.