Kenyan opposition leader Raila Odinga on Sunday rejected an offer to form a unity government to end an electoral dispute that has sparked deadly ethnic violence in the East African country. Odinga also said his party would hold rallies across the country Tuesday, raising the prospect of renewed violence after a relative calm set in. There have been isolated ethnic clashes over the weekend and police fired tear gas to disperse protesters in the coastal tourist town of Mombasa. "If there is any bloodshed during these rallies it will be the government's responsibility," Odinga told a news conference. Odinga said President Mwai Kibaki, re-elected by a narrow margin in a vote count that international observers say was deeply flawed, "cannot offer us anything because he did not win the election." "There cannot be peace without justice," he said. "We want a mediator. We want a properly negotiated settlement, not a coalition government." He welcomed the expected arrival this week of Ghanian President John Kufuor, chairman of the African Union, to mediate. Kibaki offered to form a government of national unity on Saturday during talks with the top U.S. diplomat for Africa, Jendayi Frazer. Frazer was still in Nairobi on Sunday, but it was not known whether she would meet again with the rival politicians. The violence, which has killed more than 300 people and forced some 250,000 from their homes across the country, eased over the weekend. At a small church in Nairobi's Kibera slum that was set ablaze during the crisis, 30 people gathered before a charred crucifix surrounded by burned-out stained glass windows. "We ask you to be with those who tried to kill you and destroy you," the Lutheran pastor told the congregation, standing because smashed pews were piled up in the back of the church. "Forgive them Lord because they know not what they do." The crisis following the Dec. 27 election with a deeply flawed vote count has pitted Kibaki's Kikuyu people against Kenya's other tribes, and brought chaos to a country of 34 million people that had been one of East Africa's most stable democracies. In the countryside, with the continued threat of ethnic attacks, thousands fled their homes, escorted by soldiers as they streamed down roads strewn with corpses, burned out vehicles and downed power lines. Tens of thousands of people are hungry, cut off from supplies by the crisis, which closed down shops and transport across the country. What food is available has tripled in price, putting it out of the reach of the poor. The United Nations tried to help Sunday, sending 20 truckloads of grain, pulses and vegetable oil that had been stuck in Mombasa port on the southeast coast. Vigilante roadblocks and other insecurity had halted shipments. The convoy of trucks left without an expected armed police escort but a police vehicle was seen racing to catch up about 100 kilometers (60 miles) outside Mombasa. The food was destined for some 100,000 "people who are in dire need" in Nairobi, the capital, and troubled Eldoret city in Odinga's stronghold in the central Rift Valley, according to U.N. World Food Program logistics officer Lemma Jembere. After Kibaki met with Frazer on Saturday, the president said he was "ready to form a government of national unity that would not only unite Kenyans but would also help in the healing and reconciliation process," according to a government statement. Odinga had softened his stance after two meetings with Frazer, unexpectedly withdrawing his call for Kibaki to step down, his spokesman, Salim Lone, told The Associated Press on Saturday night. But the opposition leader told reporters Sunday that "we are not interested in Kibaki's position. We want a durable solution." It would be nearly impossible for Kibaki to govern without opposition support. In parliamentary balloting, Odinga's party won 95 of 210 legislative seats and half of Kibaki's Cabinet lost their seats. Makeshift roadblocks have been set up along main roads by young men enraged over Kibaki's re-election.