Zimbabwe's opposition leader has fled to a Western embassy after pulling out of the presidential runoff, and dozens of his supporters were hustled away by police in a raid on party headquarters Monday.

American, African and European leaders denounced the developments in this southern African country, but President Robert Mugabe appeared determined to press ahead with Friday's vote.

Opposition Movement for Democratic Change leader Morgan Tsvangirai had returned to Zimbabwe a month ago to campaign, even though his party said it believed he was the target of a state-sponsored assassination plot. Since then, his top deputy has been arrested on treason charges -- which carry the death penalty; he has been repeatedly detained by police; and his supporters have faced such violence that Tsvangirai said Sunday he could not run.

Dutch officials said Monday that Tsvangirai sought shelter in their embassy in Harare a day earlier, following his announcement about pulling out of the runoff, and that he had not asked for political asylum.

Tsvangirai "asked if the Dutch Embassy could provide him with refuge because he was feeling unsafe," Foreign Minister Maxime Verhagen of the Netherlands said. "We will do what we can to accommodate his stay in the embassy," he told the British Broadcasting Corp.

There has been no request for political asylum, said Foreign Ministry spokesman Rob Dekker.

Verhagen said Tsvangirai chose the Dutch Embassy because it had no colonial past with Zimbabwe, but had been a consistent supporter of human rights. He said he expected the Zimbabwean authorities to abide by international conventions that protect diplomats and their missions, which in this case included Tsvangirai as long as he was in the embassy.

Condemnation of Mugabe poured from Germany, New Zealand, Australia, Britain and France.

"In forsaking the most basic tenet of governance, the protection of its people, the government of Zimbabwe must be held accountable by the international community," U.S. Secretary of State Condoleezza Rice said in a statement.

Western powers outraged at the turmoil in Zimbabwe began pushing Monday for the U.N. Security Council to condemn the violence and insist on a fair presidential election. They expect opposition from Zimbabwe's two biggest trading partners, South Africa and China.

Tsvangirai won the first round of the presidential election on March 29, but did not gain an outright majority against 84-year-old Mugabe. That campaign was generally peaceful, but the runoff has been overshadowed by violence and intimidation, especially in rural areas. Independent human rights groups say 85 people have died and tens of thousands have been displaced from their homes, most of them opposition supporters.

In Harare, opposition party spokesmen would not immediately comment Monday. But David Coltart, a prominent party member, said he had heard that not only was Tsvangirai at the embassy, but other top leaders had gone underground.

"Virtually the entire leadership is hiding in Harare," Coltart said.

With the opposition cowed, Mugabe's government said Friday's vote will go ahead -- with Tsvangirai's name on the ballot. The intent appeared to be to humiliate the opposition.

The prospect of a sham election drew strong criticism from the international community. But Zimbabwe's longtime, increasingly autocratic ruler has shown little concern for the world's opinion. His police entered opposition headquarters Monday, even as foreign election observers watched.

Movement for Democratic Change spokesman Nelson Chamisa said most of the people taken away from party headquarters on Monday were women and children seeking refuge after fleeing state-sponsored political violence. He said police also seized computers and furniture.

Police spokesman Wayne Bvudzijena said police took 39 people from the opposition headquarters as part of an investigation into political violence. He said they had been taken to what he called a "rehabilitation center" for interviews.

After a similar raid in April, police detained scores of people they accused of being responsible for postelection violence. A court later released them.

In announcing his withdrawal from the runoff, Tsvangirai had said such harassment and violence against his supporters had made the balloting impossible.

Word of Tsvangirai's withdrawal spread in Zimbabwe by cell phone text message and the local "bush telegraph." Some supporters said they felt abandoned, but others said Tsvangirai had no choice, given the violence.

Militant groups roamed the capital Monday and cars and buses displayed Mugabe posters and fliers. One motorist said he hung a Mugabe party bandanna given to him by friends on his car mirror in hopes it would protect him from attacks.

Roy Bennett, treasurer of Tsvangirai's party, told The Associated Press in Johannesburg, South Africa, that the party was not turning its back on elections. He urged the Southern African Development Community and the African Union to launch negotiations aimed at bringing members of the opposition and moderate members of Mugabe's ZANU-PF party together in a transitional authority that would create conditions for free and fair presidential voting.

He said Mugabe would not be welcome on the transitional authority or in a future government.

The issue of Mugabe's role is believed to have derailed previous attempts to resolve Mugabe's crisis by creating a coalition government. But Bennett said ZANU-PF would have to yield now in the face of growing international pressure. ZANU-PF, he said, risked being "totally isolated and totally rejected by the African countries as well as the world at large."

South African President Thabo Mbeki has been mediating between Mugabe and Tsvangirai for more than a year under Southern African Development Community auspices. Bennett, though, appeared to be calling for a new initiative. The Movement for Democratic Change has said Mbeki should step down, accusing him of bias in Mugabe's favor.

Mbeki spokesman Mukoni Ratshitanga said a South African negotiating team was in Zimbabwe on Monday. But Bennett said negotiations could not open until state-sponsored violence ended and Tendai Biti, the party's secretary-general, was freed. He was jailed on treason charges since June 12.

Mbeki has steadfastly refused to criticize Mugabe, saying confronting him could close the door to talks. But other African leaders have shown increasing unease, and South Africa was under pressure to speak out.

Zambian President Levy Mwanawasa, who holds the rotating chair of the development community, said Sunday a "catastrophe" was looming in Zimbabwe. He expressed frustration with Mbeki, saying he had been unable to reach him in recent days and complaining he was not sharing information about his mediation efforts.

The regional bloc was considering withdrawing its election observers from Zimbabwe, Angolan Foreign Minister Joao Bernardo Miranda told reporters before a meeting of Southern African Development Community foreign ministers in Angola. The meeting then went into closed session to hear a report from Zimbabwe's foreign minister.

In a statement Monday, African Union chief executive Jean Ping expressed "grave concern" at the violence and Tsvangirai's withdrawal.