The impromptu campaign rally ended not with cheers but panic as armed men on motorcycles, some wearing yellow-and-green T-shirts of a rival presidential contender, pulled up to the small crowd and fired into the air.

Nearly everyone ripped off the red-white-and-blue T-shirts of their candidate and fled down the pitted side streets of the Cite Soleil slum, rally organizer Pierre Joseph Laimay said. He got people to campaign for Charles Henri Baker, a factory owner who is one of 19 candidates in Sunday's presidential election, by handing out T-shirts and money for water and bus fare — and had hoped to make a little money himself from the campaign for his efforts.

As the others fled, he stood his ground.

"If they were going to kill me, they were going to have to do it with my T-shirt on," said the 45-year-old father of three. He looked nervously down the street.

The U.N. representative in Haiti, Edmond Mulet, called the "volatile political climate" a Haitian tradition. Multiple candidates have reported attempts on their lives — a credibility-building boast in a country where election days have long been synonymous with voter intimidation and massacres.

Recent elections, including the 2006 vote that put President Rene Preval in power, have been notably calmer, though not free of violence. But any disturbances could derail this year's vote, which already must contend with a rapidly spreading cholera epidemic and the fallout from the devastation of last January's earthquake.

The next president will oversee billions of dollars in U.S. and other foreign reconstruction aid. The front-runners are divided on what should be done with it. Nearly all are criticizing the post-quake inaction of Preval, who was barred from running again.

His new Unity party has put up Jude Celestin, the head of the country's state-run construction company, who would be expected to carry on Preval's policies, and possibly retain the current prime minister and much of the Cabinet.

"This period coming up is going to be critical for the nation state to make some decisions about how this country rebuilds itself over the coming years," U.S. Ambassador Kenneth Merten said. Washington, which is Haiti's largest international donor, has backed the decision to go forward with the elections and provided $14 million in support.

On Monday night, Baker's supporters clashed with Celestin's supporters near the southern coastal town of Jeremie. Conflicting reports said one, two or three people were killed by gunfire.

Sen. Joseph Lambert, the head of Celestin's campaign, said in a Wednesday interview that the attack was an attempt to kill the candidate, who was in a convoy of campaign vehicles. He said Celestin is a target because he is likely to win. Baker has said two of his supporters were killed "in reaction to the success" of a recent Baker rally in nearby Jeremie.

Celestin's campaign said the incident should not affect the timing of the vote.

"Obviously, we have seen elections held in Afghanistan and Iraq ... a small incident like this won't stop ours," Lambert said.

More clashes wre expected as campaigning winds down. Haitians are often paid small amounts, or get a little gas money or other small gifts, to attend and cheer on candidates. And with so many people in the race, even a small percentage of votes can propel someone into a runoff or make them a spoiler, provoking fierce contests even among those who have little chance of becoming president.

Violence has been a factor in Haitian elections throughout its history. From 1957 to 1986, the country was ruled by the father-and-son Duvalier dynasty, which maintained itself through fraudulent elections, executions and torture. The year after the son, Jean-Claude, fled Haiti, elections were canceled when the dictator's loyalists massacred at least 23 people waiting to vote.

Bernice Robertson, a senior Haiti analyst for the International Crisis Group, said violence persists partly because there has been little punishment in a country that has long lacked a reliable justice system.

Robertson and other observers fear that if the violence and protests get any worse, people will be too scared to vote in large numbers. "For the elections to be a success we need some level of peace so that people can go out to vote to get a reasonable turnout," she said.

The causes of the most recent violence are murky.

Protests broke out last week against the Haitian government and the United Nations, whose peacekeepers are suspected of inadvertently bringing cholera to Haiti. The disease, never before found in Haiti, has killed more than 1,400 people and sickened nearly 25,000 over the past month. Authorities said this week that 400,000 could fall ill in the coming year.

Mulet blamed the violence on several groups including gangs and former members of the army, which was disbanded more than 15 years ago. Other observers have said the U.N.'s slow and dismissive response to the rumors about its soldiers' link to cholera simply enflamed anger.

The election cycle started, months before the Jan. 12 quake, under boycott threats. Many were angered over the disqualification on a technicality of ousted former President Jean-Bertrand Aristide's Fanmi Lavalas Party, though several people previously associated with the movement are running Sunday.

There were also suspicions, raised before Celestin was chosen, that Preval would use the election to promote his own candidate.

That concern is fueling clashes between police and demonstrators in the capital.

"They are trying to impose Celestin, that is all they do. They want to keep us oppressed and let us die," Cymorin Bonenfant, a protester, said Wednesday.

Lambert said the Unity campaign expects both a first-round victory and accusations of fraud.

Preliminary results aren't expected until Dec. 7, with a likely runoff scheduled in January. A 10-day appeals period in December will follow the preliminary results.

The international community and Haitian government are resisting calls to postpone the election because of logistical challenges caused by the earthquake such as lost voter identification cards and destroyed polling stations. Hundreds of thousands of dead people, many of them killed in the earthquake, are still on the rolls.

An estimated 4.5 million living people are registered to vote at more than 11,000 polling stations.

Alcendor Jean-Denoit, a 66-year-old carpenter, said he just hopes the election won't be another problem itself.

"We just had a major earthquake. We're hoping that there won't be more violence and more lives lost," he said.


AP Television News cameraman Pierre-Richard Luxama contributed to this report.