PORT-AU-PRINCE— A presidential runoff that had already been delayed once and faced deep public skepticism was put on hold indefinitely Friday, as Haiti's leaders sought to negotiate a resolution to what threatens to become a constitutional crisis. The Provisional Electoral Council decided to postpone Sunday's vote because there is "too much violence throughout the country,'' council president Pierre-Louis Opont said at a news conference. In recent days, a number of election offices across the impoverished nation have been burned and the capital has been rocked by violent opposition protests calling for a halt to the runoff. The council did not set a new date for the vote. It also did not say whether an interim government would take power after Feb. 7, when President Michel Martelly is required to leave office under the Constitution, or if he would remain until a replacement is elected. Martelly had been expected to address the issue in a speech to the nation Friday evening, but he canceled his address as thousands of protesters erected flaming barricades, smashed car windows and hurled rocks at police in Port-au-Prince. Instead an extraordinary council of ministers was convened to discuss public order and security. Government opponents have insisted that the first round of presidential balloting Oct. 25 was marred by massive fraud in favor of the president's hand-picked successor, businessman Jovenel Moise. The runoff was originally supposed to be held Dec. 27, then rescheduled for Sunday. Jude Celestin, also a businessman and the other candidate in the runoff, said he would boycott the vote, though his name remained on the ballot. Neither candidate immediately returned phone messages seeking response to the electoral council's decision. In a statement, Celestin's "Group of Eight'' opposition alliance welcomed the "fighting spirit of the Haitian people." Protests have grown increasingly violent in recent days, prompting the council to conclude it was too risky to try to hold the vote. Haiti has only a shaky handle on security even with the assistance of troops and police from a U.N. peacekeeping force that has been in the country since a 2004 uprising ousted then-President Jean-Bertrand Aristide. Schools that serve as election centers and voting stations in various towns have been attacked and set on fire in recent days, and election materials in a border town were hijacked by gunmen, Opont said. Recent opposition-stoked protests in Port-au-Prince have ramped up the tension with rock-throwing partisans and burning street barricades. Thousands of demonstrators cheered in celebration Friday after hearing the vote would be postponed. Groups of mostly young men then proceeded to Petionville, a hillside district that is home to some of Haiti's wealthiest citizens, where they smashed windows, set vehicles alight and threw rocks at riot police. Security guards fired into the air. In the evening, the smoldering remnants of scores of flaming barricades could be seen in downtown Port-au-Prince. Motorists were forced to swerve around burnt tires, shattered glass and piles of rocks, but roadside eateries began to reopen. There has been growing concern that a flawed runoff might push the perennially volatile country of 10 million people to the edge of tumult, rolling back a decade of relative political stability and putting the brakes on foreign investment. Celestin recently told The Associated Press that Haiti was "moving toward a selection, not an election.'' He said the U.S. and other foreign governments that monitor Haiti were complicit for supporting flawed elections. Haiti's Senate and various religious, business and civil-society groups had called for a halt to Sunday's runoff due to public suspicion of fraud and concerns about instability. Martelly had said the runoff would go on as scheduled and accused the opposition of trying to derail the vote with bogus accusations so a transitional government they would dominate could be set up. The United Nations, international election observers and foreign governments urged Haiti's feuding political actors to negotiate a solution to an electoral impasse that threatens to soon become a constitutional crisis. Haiti's charter requires a new government to take power Feb. 7, but election authorities say there is now no chance the country will meet that deadline to pick the next president. It is unclear whether an interim government will be set up, or another solution may be reached. In a statement, U.N. Secretary-General Ban Ki-moon urged Haitians to work toward "peaceful completion of the electoral process without delay." Government officials have not addressed the impasse publicly since Friday afternoon, when the Provisional Electoral Council postponed the runoff a second time without naming a new date for the vote. A day after protesters set fires and smashed windows, a few thousand anti-government demonstrators again took to the streets of Port-au-Prince on Jan. 23. Young men threw rocks and lit tire barricades on fire downtown, sending black smoke billowing into the air. Many called for new elections and the immediate removal of President Michel Martelly. "He cannot stay a second longer,'' said Frantzo Nepha, an unemployed 24-year-old. Ruling party candidate Jovenel Moise said he was mystified that electoral authorities would again postpone the runoff without immediately providing a new date. The vote was originally supposed to be held Dec. 27. Moise, whose top finish in the first round prompted allegations of vote-rigging, told reporters he was believes he is the people's choice and called for the runoff to be held soon and peacefully. "Our generation has a responsibility to show other countries in the world that we are a civilized nation,'' he said. Many Haitians are exasperated by the political infighting and disruptive protests. "It seems like politicians want to drag the Haitian people backward,'' said Karine Fenelon, as she picked out oranges at a roadside fruit stall.