ZIMBABWE, June 26 – Zimbabwe’s opposition leader Morgan Tsvangirai has issued a final warning to President Robert Mugabe ahead of Friday’s run-off presidential poll.
Speaking to the UK’s Times newspaper, Tsvangirai said the time for negotiations would be over if Mugabe went ahead with the vote.
On Wednesday, former South African leader Nelson Mandela said Zimbabwe was suffering a "failure of leadership".
Southern African leaders have called for the run-off to be postponed.
The leaders from the Southern African Development Community (Sadc) said conditions did not permit a free and fair election.
Nelson Mandela makes his first public remarks criticising Robert Mugabe
Tsvangirai, who has pulled out of the run-off over fears of increasing political violence, has called for foreign help to end the crisis.
Mugabe has said his government was open to negotiations with "anyone" but only after Friday’s elections.
Speaking to The Times by telephone, Tsvangirai said negotiations between his Movement for Democratic Change (MDC) and the ruling Zanu-PF would be over if Mugabe declared himself the winner of the vote.
"How can you call yourself an elected president? You are illegitimate and I will not speak to an illegitimate president," he said of Mugabe.
The opposition Movement for Democratic Change (MDC) says some 86 of its supporters have been killed and 200,000 forced from their homes by militias loyal to the ruling Zanu-PF party. The government blames the MDC for the violence.
Tsvangirai said he withdrew from the election on Sunday over fears for the lives of his supporters, and because the poll could not be free or fair.
The government and Zimbabwe’s election authority insist Friday’s vote will go ahead because Tsvangirai’s withdrawal came too late to prevent his name appearing on the ballot paper and was therefore invalid.
Mugabe officially came second to Tsvangirai in the first round in March.
Speaking at a dinner in London to mark his 90th birthday, Mandela said: "We watch with sadness the continuing tragedy in Darfur. Nearer to home we have seen… the tragic failure of leadership in our neighbouring Zimbabwe."
Mbeki’s policy of "quiet diplomacy" has been criticised for its failure to resolve the crisis in Zimbabwe.
Nelson Mandela spoke few words but they will carry immense weight simply because of who he is, says our correspondent.
The crisis has drawn growing international condemnation of Mugabe and his government.
The US has said it will not recognise the results of the vote.