President Robert Mugabe is expected to be declared the winner of Zimbabwe's widely condemned election on Sunday and prepare to confront his critics at an African Union summit the next day.

The West stepped up calls on Saturday for action to end Mugabe's 28-year rule after he went ahead with Friday's presidential run-off despite opposition leader Morgan Tsvangirai's withdrawal because of killings of his supporters.

"The Mugabe regime held a sham election," said US President George W Bush, adding Washington would impose new sanctions as well as urge the UN Security Council to implement a travel ban on Zimbabwean officials and an arms embargo.

But although a number of African leaders have voiced disquiet with Mugabe in the past few days, foreign ministers preparing for the African Union summit in Egypt on Monday suggested the AU would not support Western calls for sanctions.

Mugabe, 84, accused by the West and the opposition of being responsible for Zimbabwe's political and economic crisis, has said he would go to the summit to challenge African leaders who had been critical of him about their own behaviour in power.

Zimbabwean electoral officials said on Saturday they hoped to be able to announce the election result on Sunday. Mugabe could be sworn in within a few hours of the result.

Tsvangirai beat Mugabe in a March 29 presidential poll but failed to win the absolute majority required to avoid a run-off, according to the Electoral Commission's results.

He withdrew from the run-off a week ago and took refuge in the Dutch embassy in Harare, saying almost 90 of his supporters had been killed by militias loyal to Mugabe.

Government sources said on Saturday Mugabe, a former guerrilla leader who has been in power since independence from Britain in 1980, seemed to be heading for a big election win.

"The tallies are indicating that despite the wishes of our detractors and the propaganda of our enemies, the voter turnout was very big and that we are going to see a landslide victory," said one source, who declined to be identified.

On Friday, witnesses and election monitors reported that in many areas people did not go to the polls. They said people in some places had been forced to vote for Mugabe.

Tsvangirai said millions stayed away from polling stations despite systematic intimidation.

Some AU foreign ministers preparing for Monday's summit said a power-sharing deal in Zimbabwe should be encouraged. AU mediation helped form a power-sharing government in Kenya earlier this year, ending a crisis in which 1,500 were killed.

"I think we need to engage Zimbabwe. The route of sanctions may not be the helpful one," Kenyan Foreign Minister Moses Wetangula told reporters.

Tsvangirai said last week he would not negotiate with Mugabe if he went ahead with Friday's election. South African President Thabo Mbeki has shown no sign of changing his policy of quiet diplomacy on Zimbabwe as the designated regional mediator or using South Africa's considerable economic leverage with its landlocked neighbour.

Tsvangirai's Movement for Democratic Change (MDC) said it would lobby the AU to take a firm position for a change of government in Zimbabwe.

"We should not wait for rivers of blood and the complete breakdown of order," said MDC spokesman Nelson Chamisa.

"President Mbeki has become part of the problem ... I don't know why he is trying to resurrect a regime that was rejected by the people," said Chamisa. - Reuters