PORT-AU-PRINCE, Haiti (AP) _ Supporters of Haitian presidential candidate Rene Preval erected smoldering roadblocks across the capital and occupied a luxury hotel Monday. At least one protester was killed, but U.N. peacekeepers denied witness accounts that they had shot him.

As Port-au-Prince descended into chaos, Preval returned to the capital for the first time since the election Tuesday. He was the clear winner with about 90 percent of the votes counted, but supporters claimed electoral officials were tampering with results to prevent him from getting the majority he needs to avoid a runoff.

Barricades made of old tires were ablaze across the capital, sending plumes of acrid black smoke into the sky. Protesters let only journalists and Red Cross vehicles pass.

``If they don't give us the final results, we're going to burn this country down!'' a protester screamed.

The election will replace an interim government installed after former President Jean-Bertrand Aristide was ousted in a bloody rebellion two years ago. A popularly elected government with a clear mandate from the voters is seen as crucial to avoiding a political and economic meltdown in the Western Hemisphere's poorest nation. Gangs have gone on kidnapping sprees and factories have closed for lack of security.

Preval arrived in the capital aboard a U.N. helicopter from his rural home in north Haiti.

``We have questions about the electoral process,'' he told reporters after meeting with the top U.N. official in Haiti and ambassadors from the United States, France, Canada and Brazil. ``We want to see how we can save the process.''

Preval also planned to meet with the interim prime minister and president.

Interim Prime Minister Gerard Latortue appealed for calm in a nationally broadcast address. ``People, don't stay in the streets,'' he said. ``I'm asking you to go home. ... The transitional government is not stealing your vote.''

In the middle-class Tabarre neighborhood, Associated Press journalists saw the body of a man on a street, blood soaking Preval's image emblazoned on his T-shirt. Dozens of witnesses said Jordanian U.N. peacekeepers in a jeep opened fire, killing two people and wounding four. The body of the second victim was not seen.

``We were peacefully protesting when the U.N. started shooting. There were a lot of shots. Everybody ran,'' said Walrick Michel, 22.

U.N. spokesman David Wimhurst first denied that peacekeepers fired any rounds, then later said they had fired in the air.

``We fired two warning shots into the air and we didn't injure anyone,'' he said.

In the Petionville neighborhood in the hills east of Port-au-Prince, thousands of screaming protesters poured into the Montana Hotel, where election officials had been announcing results. Blue-helmeted U.N. peacekeepers armed with assault rifles looked on from the grounds and the roof. No violence was reported.

Protesters waving Preval campaign posters and tree branches jumped up and down in unison, chanting: ``Now is the time! Now is the time!'' Dozens somersaulted fully clothed into the pool, turning the water into froth as they splashed around _ a rare treat in a country where most people lack running water.

Protesters stretched out on chaise lounges and ran up and down the hotel stairs past rooms costing $200 and more a night.

Nobel Peace Prize laureate Desmond Tutu, who is visiting Haiti, came out of his suite to appeal for calm. One of his security agents said the South African had refused to be evacuated by a helicopter plucking guests from the roof.

U.N. peacekeepers controlled access to a separate part of the hotel that was being used as an election center, and U.N. Huey helicopters clattered overhead.

After several hours, the crowd began to file out of the hotel.

``We came looking for someone to give us the real results,'' said a 30-year-old Preval organizer who identified himself only as ``Sanpeur.'' ``We made them leave because we don't want disorder. We did not come here looking for violence.''

The Bush administration urged Haitians to refrain from violence and to respect the results of the election.

State Department spokesman Sean McCormack said that once results are announced, all parties should ``come together and work together'' for the betterment of the country.

With about 90 percent of the vote counted, Preval was leading with 48.7 percent, Haiti's electoral council said on its Web site. His nearest opponent was Leslie Manigat, another former president, who had 11.8 percent.

But of the 2.2 million ballots cast, about 125,000 ballots have been declared invalid because of irregularities, raising suspicion among Preval supporters that polling officials were rigging the election.

Another 4 percent of the ballots were blank but were still added into the total, making it harder for Preval to obtain the 50 percent plus one vote needed.

Jacques Bernard, director-general of the nine-member electoral council, denied accusations that the council voided many votes for Preval.

Council member Patrick Fequiere said Bernard was releasing results without notifying other council members, who did not know where Bernard was obtaining his information. And another council member, Pierre Richard Duchemin, said he was being denied access to the tabulation process.

``According to me, there's a certain level of manipulation,'' Duchemin said, adding that ``there is an effort to stop people from asking questions.''

___

Associated Press Writer Andrew Selsky contributed to this report.