WASHINGTON, July 7 (Reuters) -- The Organization of American States
                  decided on Friday to pull its electoral observers out of Haiti ahead of Sunday's
                  second-round vote in congressional and municipal elections, citing tainted results
                  flavoring ex president Jean-Bertrand Aristide's party.

                  Repeating its withdrawal from the controversial reelection of President Alberto
                  Fujimori in Peru in May, the OAS said it was forced to suspend its observer
                  mission in Haiti because the principle of one-person one-vote had been violated.

                  Opposition candidates pulled out of Sunday's congressional and municipal
                  elections in the hemisphere's poorest country, which is still struggling to build
                  democratic institutions after decades of dictatorship.

                  They complained results of the May 21 first-round vote were miscalculated to
                  give Aristide's Lavalas party a strong lead.

                  The OAS, which observed the May vote, said Haiti's election body calculated the
                  results in a way that gave Lavalas more outright victories in Senate seats than it
                  was due. Candidates needed a simple majority to win in the first round.

                  "The OAS electoral observation mission has determined that, according to
                  provisions of Haiti's own electoral legislation, the final results for the senate
                  elections as proclaimed by the Provisional Electoral Council are incorrect," the
                  OAS said in a statement.

                  "The mission cannot consider them either accurate or fair," it said.

                  "As a result, the mission announced it will not observe the second round of the
                  electoral process scheduled to take place on Sunday, July 9th," the statement
                  said.

                  The United States slammed Haiti's government earlier on Friday for not holding
                  runoffs of the tainted senate races on Sunday.

                  State Department spokesman Richard Boucher told reporters that the methods
                  used to tabulate the results were incorrect and cast doubts over the whole
                  election.

                  "The failure of the Haitian government and the electoral authorities to use the
                  proper method in determining winners in the senate election certainly calls into
                  question the credibility of the entire Haitian election process," he added.

                  The U.S. government, the United Nations and the OAS, which groups all nations
                  of the hemisphere except Cuba, had pressed Haiti to hold the runoffs.

                  But Haitian Primer Minister Rene Preval, returning on Wednesday from a summit
                  of the Caribbean nations organization Caricom in Saint Vincent, said the results
                  given by Haiti's Provisional Electoral Council (CEP) were final.

                  "We regret the decision that they won't monitor the election," CEP spokesman
                  Frantz Faustin said in Port-au-Prince, the Haitian capital. "We would appreciate
                  their comments. We would welcome them if they decided to come. But we
                  respect their decision."

                  Caricom had asked the Haitian government to reexamine its vote counting
                  methods.

                  Aristide, a former Catholic priest, is widely expected to run for president and win
                  later this year.

                  Haiti's first freely elected president, Aristide was overthrown in 1991 by a
                  military coup that resulted in a reign of terror that ended in 1994 when the United
                  States sent 20,000 troops to restore Aristide.

                  Haiti's government has been paralyzed for most of the past three years after
                  parliamentary elections held in April 1997 were declared fraudulent. Preval
                  dissolved Parliament in January 1999 and has since ruled by decree.

                  Sunday's election aims to fill 19 of the 27 seats in the Senate and all 83 seats in
                  the Chamber of Deputies, as well as thousands of municipal posts nationwide.