AU-PRINCE, Rabi'II 13, 1437, January 23, 2016, SPA -- Haiti postponed a U.S.-backed presidential election as violent protests erupted on Friday after the opposition candidate vowed to boycott the vote over alleged fraud, according to Reuters. Pierre Louis Opont, president of Haiti's electoral council, said the vote scheduled for Sunday was being pushed back for security reasons. He did not say when it now might be held. Opposition candidate Jude Celestin this week vowed to boycott the election, alleging a first round vote in October was rigged to favor the ruling party candidate. An anti-government protest turned violent in the capital Port-au-Prince on Friday, and police fired at a group of people who appeared to be looting a shop. One man lay on the ground bleeding profusely, but it was unclear how he was injured. "The direction (outgoing President Michel) Martelly has taken the country is no good," said Rolando Joilcoeui, a community worker standing among thousands of people in the streets, as tear gas wafted in the air. "We've said 'no' to that regime. The election was a fraud." Swiss-trained engineer Celestin has said the government has not done enough to remedy cheating in the first round, and called the plans for the second round vote "a farce." Celestin was second in a field of 54 candidates in the October election, almost eight percentage points behind ruling party candidate Jovenel Moise. Haiti's newly appointed senators voted almost unanimously this week to postpone the vote, and the Catholic church, business groups and local election observers all warned that an election under such conditions would not lead to a credible outcome. Moise had told Reuters earlier on Friday that he expected the vote to take place as planned, and was still in campaign mode. The country of about 10 million people has struggled to build a stable democracy since the overthrow of the 1957-1986 dictatorship of the Duvalier family and ensuing military coups and election fraud. The latest round of political volatility has distracted from reconstruction after a devastating earthquake six years ago.