Tsvangirai, who says he won a March 29 presidential election and Mugabe's rule is over, flew to South Africa while his Movement for Democratic Change went to court to try to force the release of results of the vote.

The Zimbabwe High Court was due to rule on Monday whether it has the authority to rule on the MDC application. The Zimbabwe Electoral Commission is resisting and Mugabe's ruling party wants the results delayed pending a recount.

MDC officials said on Monday Tsvangirai had gone to South Africa for private talks but gave no details.

Tsvangirai said in a newspaper article that Zimbabwe was on a razor's edge.

"Major powers here, such as South Africa, the U.S. and Britain, must act to remove the white-knuckle grip of Mugabe's suicidal reign and oblige him and his minions to retire," Tsvangirai wrote in Britain's Guardian newspaper.

But South African President Thabo Mbeki, who failed last year to mediate an end to the Zimbabwe crisis, said at the weekend the post-election situation there was "manageable" and it was not the time for international intervention.

No results have emerged from the presidential vote nine days ago, fuelling opposition concern that Mugabe is buying time to organise a fight-back after his ruling ZANU-PF lost control of parliament in the March 29 election -- his biggest defeat in an uninterrupted rule since independence from Britain.

ZANU-PF and independent monitors' projections show Tsvangirai has won the presidential election but will be forced into a runoff vote after failing to win an absolute majority.

STRATEGY

ZANU-PF's strategy to stay in power includes legal challenges to some of the parliamentary results and the mobilisation of pro-government militias before any runoff.

The re-emergence of liberation war veterans, often used as political shock troops by Mugabe, has increased concern that he plans a violent response to his election setback.

On Saturday, Tsvangirai accused the 84-year-old former guerrilla leader of "preparing a war on the people".

The veterans led a wave of violent occupations of white farms as part of a government land redistribution programme.

Critics say the land reforms, in which inexperienced farmers and Mugabe cronies took over many farms, is at the centre of Zimbabwe's economic meltdown. It now suffers the world's worst hyper-inflation.

Responding to reports of fresh farm invasions by the war veterans, Commercial Farmers' Union (CFU) chief executive Hendrick Olivier said police had dispersed groups of people "claiming to be war veterans ordering farmers to vacate their farms" in Masvingo province.

"We have also received similar reports from two farms in Centenary. Reports have also been made to the police and we hope they will act as swiftly as they did in Masvingo," he said.

Agricultural officials say a majority of Zimbabwe's 4,500 or so white commercial farmers have been forced off their properties since 2000 when Mugabe launched his land reforms.

The state-run Herald newspaper quoted Mugabe as saying Zimbabweans should protect their land from former colonisers. It said he made the plea at the funeral of a relative.

Electoral rules say a runoff must be held three weeks after the release of results, meaning the longer the delay the more time Mugabe has to regroup.

Mugabe's government is widely accused in the West of stealing previous presidential and parliamentary elections, and his removal is regarded by Washington and London as necessary to rebuilding Zimbabwe's shattered economy.

Zimbabweans are struggling with inflation of more than 100,000 percent, mass unemployment and chronic shortages of meat, bread, fuel and other necessities.