COLOMBO — Police stopped about 1,000 ethnic minority Tamils from traveling to a protest to demand justice for relatives who disappeared during Sri Lanka's civil war or have been detained since the end of the conflict, causing the protest's cancellation, an organizer said Wednesday. Meanwhile, hundreds of people took part in a pro-government protest Wednesday outside the country's United Nations office in the capital, Colombo, calling for investigations into thousands of killings blamed on the Tamil Tiger rebels, who were defeated in the war. Sri Lanka's 25-year civil war ended in 2009 after government forces crushed the Tamil Tigers, who had been fighting for a separate state for Tamils in the island's north and east regions. Tamils and rights groups have said that thousands went missing during the war, allegedly at the hands of government security forces. They are demanding a UN-led international probe into alleged human rights abuses during the war, but the government has rejected the calls. Mano Ganeshan, an opposition leader who heads the commission that campaigns against the disappearances, said buses packed with about 1,000 Tamils were prevented from leaving the northern town of Vavuniya on Tuesday to make the 210-kilometer (130-mile) journey to Colombo for Wednesday's protest. He said government forces and police intimidated and warned the bus drivers not to proceed with the journey. “As the protesters were not allowed to participate, we decided to cancel the protest,” Ganeshan said. Military spokesman Brig. Ruwan Wanigasooriya rejected the allegations and said police stopped the buses to prevent possible clashes in Vavuniya. He said complaints were made to police earlier Tuesday saying people had thrown stones at the buses. Police stopped the buses from moving “in order to prevent a clash between the people in the buses and the people in the area,” Wanigasooriya said. Separately on Wednesday, hundreds of people marched across Colombo and demonstrated opposite the UN office, demanding the world body probe atrocities and crimes allegedly committed by the Tamil Tiger rebels. Ananda Perera, a spokesman for the Dead and Missing Persons' Parents Front, which organized the protest, said demonstrators handed a letter to the UN containing the details of 6,000 people, including civilians, government troops and politicians, killed by the rebels. The letter asked that UN Secretary General Ban Ki-moon initiate an investigation into the alleged killings. — AP