PORT-AU-PRINCE, Haiti (AP) _ Haitians entered election day hoping for the best. Within hours, ballot boxes were ripped to pieces, protesters were on the streets and nearly every presidential hopeful was united against the government. Add it to Haiti's list: Already reeling from a catastrophic earthquake, one of the world's poorest economies, storms, a deadly cholera epidemic and unrest over U.N. peacekeepers, the Caribbean nation could now be on the edge of full-on political turmoil. The chaos in Sunday's voting united most of the top presidential candidates against the president's heir apparent - Jude Celestin, head of the state-run construction company and beneficiary of a well-financed campaign. Allegations ranging from outright fraud to polling-place disorganization that disenfranchised many Haitians nearly brought the election to a halt. Polling places opened late, voters could not find their names on lists, and some polling places were ransacked by thugs. The United Nations cited ``numerous incidents that marred the elections.'' Observers from the Organization of American States canceled an afternoon news conference, releasing a statement hours later that they were ``in the process of evaluating and analyzing the information gathered.'' The discontent boiled into a potential political crisis at about 2 p.m., when 12 of the 19 presidential candidates - including nearly every major contender - gathered in a hotel ballroom to join hands, denounce President Rene Preval and call for the election to be canceled. ``It is clear that the government of Rene Preval, in agreement with the (electoral council), is putting into execution the plan hatched to tamper with the elections ... with the help of the official political party and its candidate, Jude Celestin,'' independent candidate Anne Marie Josette Bijou read aloud. The other candidates joined the crowd in applause. The crowd, which had burst into Haiti's national anthem when the candidates arrived, chanted ``Arrest Preval!'' Protesters took to the streets, and demonstrations demanding the balloted be nullified stretched into the night. Crowds surged through the streets carrying tree branches and campaign posters, decrying the vote and jubilantly claiming victory for their candidates. The Haitian government had no immediate response to the criticism. But the electoral council held an evening news conference to say the candidates' protest had no legal weight. It said there had been irregularities at only 56 of nearly 1,500 voting centers, but did not explain how it arrived at that figure. ``If they declare that one of these candidates won, are they going to say they don't want to be elected?'' council official Pierre Louis Opont mused after a fifth Haitian reporter asked the officials to respond to the presidential candidates' appeal. Results were not likely until Dec. 7, and run-offs were expected for the presidential and nearly all senatorial and parliamentary races. Some polls and election observers said opposition candidates appeared to be doing well in the contest with Celestin. The strongest appeared to be Mirlande Manigat, 70-year-old former first lady whose husband was helped to power and then deposed by a military junta; popular musician Michel ``Sweet Micky'' Martelly and Jean-Henry Ceant, a lawyer with backing from supporters of exiled ex-President Jean-Bertrand Aristide's disqualified Fanmi Lavalas party. On Sunday afternoon they and nine of their ostensible rivals joined hands in triumph as they accused Preval of conspiring to ``perpetuate his power and keep the people hostage to continue their misery.'' The biggest problem in Sunday's vote appeared to be confusion. Many voters had no idea where to vote, while others arrived at polling stations to find that their names were not on the rolls. Some found their names on one list, outside a voting-room door for instance, only to find that they were not on the list inside. ``I have been here since six in the morning and I can't find my name on the register. I have had my (voting) card since 2006. I am going home,'' said Derissaint Dor, a 57-year-old resident of the capital. There were also reports of violence and intimidation, claims of stolen ballot boxes and allegations of ballot-stuffing. Haitian radio reported one man was shot to death at a polling place in rural Artibonite. Electoral officials said another was killed in southern Haiti. In the town of Grande Riu Du Nord, about 12 miles (20 kilometers) east of Cap-Haitien, youths sacked a polling station and scattered thousands of ballots. Photos obtained by the AP showed that some of the ballots apparently had been filled out. More were burned in a road. The motives in the attack were unknown. At another voting place in the St. Philomene neighborhood, a woman complained that young men were taking advantage of the chaos to vote multiple times. The allegation could not be confirmed because a crowd of one candidate's supporters swarmed around two AP journalists and forced them to leave the area, threatening a photographer. The protest by many of the president contenders threw the entire election into question. Though the electoral council insisted that all will proceed normally, demonstrators will not likely accept results quietly, especially if they favor the government's candidate. Representatives of Haiti's major international donors, including the ambassadors of the U.S., Canada, France and the European Union, met after the candidates' declaration to discuss the situation, said Organization of American States Assistant Secretary-General Albert Ramdin, who is in Haiti to monitor the elections. ``We are all concerned about the possibility of violence because we don't want to see people lose lives in a process that should be democratic,'' Ramdin said. Tensions are already high following a series of deadly clashes earlier this month between U.N. peacekeepers and demonstrators who suspected them of being the source of the rapidly spreading cholera outbreak. At stake in the election is the post-quake reconstruction project. The next president is expected to oversee billions in promised rebuilding aid, and would have veto power over the commission co-chaired by former U.S. President Bill Clinton and the current prime minister. Clinton is also trying to encourage foreign investment in tourism, agriculture and other areas. Most of that money, however, is contingent on the Haitian government being certified as a good, stable and non-corrupt partner. Gunfire was heard in some sectors overnight, but Monday morning was quiet as people waited to hear what their leaders and potential leaders would say.