Zimbabwe authorities ruled on Wednesday that a June 27 presidential vote would go ahead despite the withdrawal of the opposition and a storm of international condemnation. Zimbabwe Electoral Commission chairman George Chiweshe said Tsvangirai's withdrawal last Sunday had been filed too late to have any legal effect. Accordingly, the commission does not recognize the purported withdrawal. We are, therefore, proceeding with the presidential election run-off this Friday as planned.” Opposition leader Morgan Tsvangirai, who pulled out of the contest against President Robert Mugabe because of attacks on his followers, said the vote was a sham and called for the African Union, backed by the United Nations, to lead a transition in Zimbabwe. Tsvangirai spoke at a press conference at his home after leaving the Dutch embassy where he took refuge after announcing the pull-out last Sunday. But he returned to the embassy later. Tsvangirai told reporters during the brief news conference: “I am asking the AU and SADC (Southern African Development Community) to lead an expanded initiative supported by the U.N. to manage what I will call a transitional process.” The opposition leader said the election would not be accepted either by Zimbabweans or the world. He called on the AU to discuss the crisis next weekend at a summit in Egypt. Pressure has mounted both inside and outside Africa to call off the vote since Tsvangirai withdrew. Mugabe, 84, is now certain to be elected to extend his 28-year rule. Human rights organisations, Western powers and Tsvangirai's Movement for Democratic Change accuse the veteran leader of launching a campaign of murder and intimidation after he and his ZANU-PF party lost elections on March 29. Several Western nations, including Britain and the United States, have urged the world to isolate Mugabe and declare his presidency illegitimate if there is not a free and fair ballot. In the first concrete step to punish Mugabe for a wave of violence that resulted in Tsvangirai's withdrawal, former colonial power Britain said it was preparing tougher sanctions against specific members of Zimbabwe's government. Kenyan Prime Minister Raila Odinga told reporters: “Zimbabwe right now is a disaster in the making,” while Foreign Minister Moses Wetangula described the crisis as a blot on Africa.