KINSHASA (Reuters) - Congolese police and U.N. peacekeepers patrolled the capital Kinshasa on Monday hours after the announcement of an election run-off was overshadowed by battles between soldiers loyal to the two leading candidates.

U.N. sources said five people were killed during fighting on Sunday night between soldiers loyal to President Joseph Kabila and followers of former rebel chief Jean-Pierre Bemba as the provisional results from historic July 30 polls were announced.

Kabila, with 44.81 percent of the votes, finished well ahead of his rival Bemba, who had 20.03 percent, but failed to gain enough votes to win the presidency outright in the first round. The two will face each other in a run-off on October 29, electoral officials said.

"We were in front of our televisions waiting for the results when our friends called from town saying there was shooting. This is chaos," said Alphonse, a taxi driver who lives in N'Djili, an outlying Kinshasa district.

There was sporadic shooting through the night but the centre of Kinshasa was calm on Monday. Tank tracks marked a main boulevard where Kabila's presidential guard, Congolese policemen and U.N. peacekeeping troops were on patrol.

The middle of the city, which is normally bustling, was nearly empty save for a handful of pedestrians inspecting spent bullet casings and the bodies of two men lying in the street.

There was still confusion over who had started the fighting on Sunday night.

"Soldiers in civilian clothes came along here and attacked Bemba's office. Bemba's men fought back and that's how these people were killed," said Jean-Pierre Paul, a Kinshasa resident in his 20s who said he witnessed the fighting.

Another man said Bemba loyalists had opened fire on the police and U.N. peacekeepers.

Last month's polls were meant to draw a line under a decade of conflict and chaos in Democratic Republic of Congo, where a 1998-2003 war sparked a humanitarian crisis that has killed more than 4 million people.

Despite continued insecurity in the lawless east and hostile campaigning in the capital, the elections, which were overseen by over 17,000 U.N. peacekeepers backed up by a smaller European Union force, were generally peaceful and considered a success.

However, they have underlined deep political and ethnic divisions in the vast central African nation.

Sunday's violence, which saw heavy fighting and armoured vehicles appearing on the streets, was an example of the hostile environment which could accompany a second round of voting.