Zimbabwe's opposition has called on South African President Thabo Mbeki to stand down as a mediator in the wake of the elections crisis. Opposition MDC leader Morgan Tsvangirai said Mr Mbeki should be "relieved of duty" in favour of Zambian President Levy Mwanawasa. Mr Tsvangirai also said the UN should consider an international crimes court to try rights abuses in Zimbabwe. Zimbabwe's government earlier accused Mr Tsvangirai of treason. 'Orgy of violence' Mr Tsvangirai says he won the recent presidential election outright. The results have not been published. He told a news conference in Johannesburg: "We want to thank President Mbeki for all of his efforts but President Mbeki needs to be relieved of his duties." Mr Tsvangirai said he had called on the regional Southern African Development Community, under the chairmanship of Mr Mwanawasa, to lead a new mediation effort. "I have made a specific request to President Mwanawasa to say that he needs to lead a new initiative... that will expand beyond President Mbeki," Mr Tsvangirai said. He said Zimbabwe's President Robert Mugabe had "unleashed an orgy of violence against the people". Mr Tsvangirai suggested a UN crimes court similar to those in Sierra Leone and the Democratic Republic of Congo. "As I speak, our people are being murdered, homes burned, children molested, women raped," he said. Mr Tsvangirai has previously said there should be no "witch hunt" against Mr Mugabe. President Mbeki had defended his record on Zimbabwe at the UN in New York on Wednesday. Mr Mbeki met President Mugabe last Saturday and afterwards said there was "no crisis" in Zimbabwe. He defended those remarks in New York, saying dialogue was essential. "The solution to the problem of Zimbabwe lies in the hands of the people of Zimbabwe," he said. Earlier on Thursday, South Africa urged Zimbabwe's electoral commission to release the results of last month's presidential election. South African spokesman Themba Maseko told the BBC there was a fear the situation in Zimbabwe could deteriorate because the results had not been released. The Zimbabwe Electoral Commission says it cannot release the results until it investigates anomalies - a partial recount takes place this weekend. Mr Tsvangirai said: "The regime is conditioning people to believe there's a run-off. There's no run-off because we won this election decisively." The call for election results to be published was echoed on Thursday by the G8 group of major industrialised countries, the European Union and US Secretary of State Condoleezza Rice, who said Zimbabwe had become an "abomination". "It's time for Africa to step up," Ms Rice said. "Where is the concern from the African Union and from Zimbabwe's neighbours about what is going on in Zimbabwe?"