Allegations of Fraud and Corruption Mar Haiti Elections (SLIDESHOW)

Port-au-Prince - In a crowded classoom in the Cite Soleil slum, Cloudier Pierre-Louis' ballot was snatched out of her hand, quickly marked and stuffed into a ballot box, one incident among many that led a dozen Haitian presidential candidates to denounce the elections and call for the arrest of President Rene Preval.

A dozen presidential candidates - including frontunner Mirlande Manigat, 70, a Sorbonne-educated former First Lady and the popular kanpa musician Michel Joseph Martelly - accused President Rene Preval and his hand-picked successor, Jude Celestin, of conspiring to rig the elections, calling for both men's arrest during a press conference Sunday.

"I am requesting the cancellation of all electorial activities throughout the territory. What is happening now is organized robbery," Manigat told reporters.

Haiti's provision electoral commission (CEP) said elections would continue, and President Preval heralded the elections as a success.

The accusations could cause violence to spill over in a nation still reeling nearly a year after a devastating earthquake, amid a growing cholera epidemic and with thousands left off voter registration lists or made the victims of fraud, deprived of the opportunity to vote.

"I don't care if I find my name or not, I'm going to vote," said Jackson DePriest, 34, as he scanned the registation lists taped to the walls of a voting station near the Plaza St. Pierre.

Gaillot Dorsainvil, the head of the CEP, was surrounded by angered would-be voters, waving their ID cards in the air and threatening to barricade him in the cramped classroom where he cast his ballot unless granted the right to cast one of their own. "Time is up!" someone yelled.

In Cite Soleil, confrontations began as soon as the polling places opened, observers said. One man said his ballot was snatched away from him and he was ordered to vote for Jude Celestin. When he refused, he was beaten.

Dieulhomme Dumelice, a CEP observer, said angry voters were ripping ballots in half while others were stuffing as many as three ballots into the box at a time. Several voting stations were destroyed.

Haitian election officials said earlier this week that an election with less than 40 percent turnout would not be considered credible.

Martelly, flanked by Haitian hip-hop performer Wyclef Jean, led a carnivalesque demonstration to a CEP office in the Delmas neighborhood. Martelly supporters thronged the streets, singing and dancing to the beat of tin horns and steel drums, and cheering wildly when the candidate stood up to shake his hips.

"Oh, Micky, now we're safe, we have liberty! We've been searching for the man, and now we're free, oh, Micky," the supporters sang.