The certification of legislative election results from last month's runoff election will be delayed after U.S. and U.N. diplomats raised questions over the victories of more than a dozen candidates, Haitian officials said Monday. U.S. diplomats said last week they wanted a public explanation for how Haiti's election commission declared victories for 17 Chamber of Deputies candidates and one Senate candidate after they ended up with far more votes than they had when preliminary returns were announced April 4. Gaillot Dorsinvil, the president of Haiti's election commission, said in a statement that the panel would hold off on publishing the results for 19 legislative races in the March 20 runoff ``for the sake of transparency and in the best interests of the nation.'' Dorsinvil didn't say if the Provisional Electoral Council, known as the CEP, planned to recount those races or disclose any details about the 19th race, which was one more than diplomats had questioned. On Friday, the U.S. Embassy in the capital, Port-au-Prince, said the legitimacy of the legislative races would be up in the air if Haitian officials didn't offer a public explanation of the commission's results. The United Nations, which has a peacekeeping force in Haiti, also expressed concerns. The new results gave the political party of outgoing President Rene Preval 46 of the 99 seats in the Chamber of Deputies and an absolute majority in the Senate with 17 of 30 seats. That kind of presence in Parliament would give Preval's Unity party greater control over key government decisions, including who is approved as the next prime minister, Haiti's No. 2 official. On Monday, Unity protesters set up flaming barricades in a Port-au-Prince slum, calling for the election results to be respected. U.N. peacekeepers later extinguished the fires. The legislative elections were held alongside Haiti's presidential runoff, and pop singer Michel ``Sweet Micky'' Martelly was declared the official winner of the nation's top post last week in a landslide win. Martelly, a first-time politician, is scheduled to be inaugurated on May 14. Martelly, who's not a party member of Unity, called for an investigation into the election results during a visit to Washington last week. The United States and other members of the international community financed the election. Since the final results were announced, sporadic protests have also popped up in the countryside. Local radio reported Monday that demonstrators set up barricades in some communities outside Port-au-Prince. Some of the election protests have apparently turned violent. An arson attack killed one person and injured three others last week in a town near the border with the Dominican Republic. An official with the Boston-based Partners in Health aid group said the attack was ``certainly associated'' with election results while cautioning that the group was not aware of an exact motive. Haitian national police spokesman Frantz Lerebours has said he has no knowledge of the attack.