Haiti is facing a "political crisis" after Sunday's election that could hurt efforts to control the spreading cholera epidemic, UN Secretary General Ban Ki-moon said Monday.
The vote was marred by reports of fraud and calls for new balloting.
Ban said worsening security could hurt efforts to fight the cholera epidemic, which has killed more than 1,600 people and infected 50,000 since it began in October.
"The secretary general looks forward to a solution to the political crisis in the country … since any deterioration in the security situation will have an immediate impact on the efforts to contain the ongoing cholera epidemic," Ban said in a statement.
In the UN's worst-case scenario, 400,000 people could become ill, with half the cases in the next three months.
Meanwhile, the country remained tense on Monday even though the current government insisted the election was fair.
The chaotic way in which Sunday's voting unfolded has united most of the top presidential candidates against current President René Préval's preferred successor — Jude Celestin, head of a state-run construction company and beneficiary of a well-financed campaign.
Haiti election coverage: Live blog
Nicole Phillips, an attorney with the Institute for Justice and Democracy in Haiti, experienced voters' frustration first-hand.
She said she witnessed a lot of ballot-box stuffing and the intimidation of voters, who were dissuaded from casting their ballots. Others voted many, many times for a single candidate. Certain opposition candidates' ballots were removed from ballot boxes and thrown into sewage canals. Many people waited four or five hours to cast their vote only to be turned away because their names were not on the electors list.
"We saw countless individuals at many of the polling stations looking for their names on the electoral list and not seeing them and going to three, four, five electoral places and not seeing their names anywhere on the lists," Phillips told CBC News in an interview Monday.
"Haitians were very, very frustrated, and I heard a lot of people saying, 'I must vote' or 'I have to vote today; otherwise, I'm going to take it to the streets'."
The tension did spill over to Monday, which saw several, mostly peaceful, demonstrations take place in Port-au-Prince, as well as outside the capital.
Twelve of the 18 presidential candidates — including nearly every major contender — gathered in a hotel ballroom to denounce Preval and call for a new election.
P.O.V.: Should Haiti's election be annulled? Take our survey.
Others don't believe a new vote is necessary but are calling for at least an investigation into the election that did take place. Many international monitors have said it's clear there were serious irregularities in Sunday's vote and that perhaps a new election should be held.
The irregularities "make these elections, unfortunately, not up to muster by international law and Haitian electoral law," Phillips said.
She said Canada, which spent $6 million funding the elections, has to take some blame for the outcome as it released the funding that enabled organizers to go ahead with the vote fully knowing there were flaws in the process. Phillips said Canada was likely under pressure from the international community to proceed with the vote.
Foreign Affairs Minister Lawrence Cannon said in a statement that, "Canada is very concerned by incidents of violence, and reported irregularities in the electoral process."
"Canada urges the government of Haiti to exhibit a steadfast commitment to democratic principles, including respect for the integrity of the electoral process," Cannon said. "It is critical that election irregularities be addressed in a timely, transparent and thorough manner."
The U.S. had roughly 1,000 observers on the ground in Haiti, and U.S. Assistant Secretary of State Philip J. Crowley said final assessments from the Organization of American States and the joint electoral observer mission sent by Caricom, the regional body representing 15 Caribbean states, are expected Monday afternoon.
"This is an election that will determine the government that will, you know, lead the reconstruction of Haiti," Crowley said. "It's vitally important that this process produce a government that the Haitian people can support and can lead them to a brighter future."
At a press conference in Port-au-Prince on Monday, U.S.-Haitian singer Wyclef Jean, whose attempted run for the Haitian presidency was denied because he did not meet the residency requirement, said the next 24 hours are crucial.
"In 24 hours, if a decision is not made and we procrastinate, the country will rise to a level of violence we have never seen before," Jean said.
Election results are expected to be announced Dec. 7 although run-off votes will likely have to be held for presidential race and nearly all Senate and parliamentary races.
Jean urged that the vote count be accelerated and that an independent body other than the United Nations — blamed by some Haitians for the country's ongoing cholera epidemic — oversee it.
Jean said he was making his comments as an individual citizen and not as a supporter of any one candidate. He said he did cast a ballot in Sunday's vote, with some difficulty after being turned away at one polling station, and will reveal who he voted for once the new president is named.
Haiti's electoral council held a news conference to say there had been irregularities at only 56 of nearly 1,500 voting centres but did not explain how it arrived at that figure.
The chaotic election is just the latest of Haiti's woes, which include a catastrophic earthquake last January; one of the world's poorest economies; storms; a deadly cholera epidemic; and unrest over the actions of UN peacekeepers.
With so much anger and frustration acting as fuel, observers say that a declaration of victory by Celestin could be enough to plunge the country into full-on political turmoil.