WASHINGTON — President Mugabe may be losing his last friend in Africa.

The African National Congress, South Africa’s ruling party, released a statement contradicting the country’s president, Thabo Mbeki, who has been the last regional leader to defend Mr. Mugabe, who has drawn the scorn of capitals worldwide.

The statement the ANC issued yesterday criticized the Zimbabwe dictator’s handling of the March 29 presidential elections and his party’s violent crackdown on the political opposition led by Morgan Tsvangirai. It called on Mr. Mugabe not to go through with a runoff presidential election scheduled for tomorrow.

Mr. Tsvangirai emerged from the Dutch embassy in Harare, where he had sought refuge, and called for the world to send “armed peacekeepers” to his embattled land.

“I didn’t ask for any military intervention, but for armed peacekeepers,” Mr. Tsvangirai, who leads the opposition Movement for Democratic Change, told reporters.

Those words coincided with the criticism from the ruling party in South Africa. “The very legitimacy of the run-off has already been severely compromised by the actions of both Zanu-PF militants and those of state officials who do not even conceal their partiality in favor of the governing party,” the statement said.

To underscore the sentiment, South Africa’s first black president, Nelson Mandela, broke his silence on Mr. Mugabe and spoke of the “crisis of leadership” in Zimbabwe. In the audience in London for an early celebration of Mr. Mandela’s 90th birthday were both President Clinton and Prime Minister Brown. The Queen of England yesterday withdrew Mr. Mugabe’s knighthood.

The increasing pressure on Mr. Mugabe appears not to have deterred his regime. Zimbabwe’s official election board announced that the Friday vote would go ahead despite condemnations this week from the United Nations, the White House, both major presidential campaigns, and most of Zimbabwe’s African neighbors. The wave of condemnation followed Mr. Tsvangirai’s announcement that he could not participate in the June 27 elections due to the state-sponsored violence against his Movement for Democratic Change.

President Bush was particularly tough in public remarks at a meeting with the five permanent representatives to the United Nations Security Council. Calling the scheduled vote a “sham,” Mr. Bush said, “You can’t have free elections if a candidate is not allowed to campaign freely and his supporters aren’t allowed to campaign without fear and intimidation. Yet the Mugabe government has been intimidating the people on the ground in Zimbabwe. And this is an incredibly sad development.”

An Africa expert at the Cato Institute, Marion Tupy, told The New York Sun that Mr. Mandela’s mild criticism of Mr. Mugabe was disappointing. “It is disappointing to hear Mandela say only this after eight years of the deteriorating economic and political situation in Zimbabwe. Nonetheless it is indicative of the increasing isolation of Robert Mugabe among African leaders,” he said. “As long as Mugabe feels that at least South Africa is on his side, he will hold the elections on Friday and continue to hold on to power.”

A former Clinton administration Africa hand and the co-director of the Enough Project to prevent genocide, John Prendergast, said he did not put too much stock in the statement yesterday of the African National Congress. “Mbeki is still the president. The ruling party is making a statement on the basis of principle and it is important that they do that. We still have the major detail though as to who remains the president of South Africa. As long as Mbeki is the president we will see a policy of defending Mugabe.”

Last night the State Department floated the prospect that there may be a negotiated solution to the electoral standoff in Harare. A spokesman for Foggy Bottom, Thomas Casey, told the Agence France Press, “I think it’s our hope that there can be a political settlement that involves discussions among all the parties, including the ZANU-PF.” ZANU-PF is the party of Mr. Mugabe. One possibility is that there are factions within Mr. Mugabe’s party that would disobey the leader and reschedule a fair vote. An envoy of Johannesburg was in Zimbabwe’s capital yesterday to pursue the possibility of a negotiation that may result in the end of the 28 year rule of Mr. Mugabe over what was once the British colony of Rhodesia.