Outraged at the turmoil in Zimbabwe, the U.N. Security Council declared that a fair presidential vote is impossible because of a "campaign of violence" being waged by President Robert Mugabe's government.

The 15-nation council said late Monday it "condemns the campaign of violence against the political opposition ahead of the second round of presidential elections," which has resulted in the killing of scores of opposition activists and other Zimbabweans.

The move came after opposition leader Morgan Tsvangirai withdrew from the vote — reportedly fearing for his safety — and police raided his Harare headquarters, hustling away dozens of his supporters.

George Sibotshiwe, a spokesman for Tsvangirai, said the politician had received a tip that soldiers were on the way to his home Sunday, after he had announced he was pulling out of the runoff scheduled for Friday.

Sibotshiwe would not reveal the source of the tip and said the soldiers' intentions were unclear. But "the moment you have soldiers coming your way, you just run for your life," Sibotshiwe said. "The only way he can protect himself is to go to an embassy."

Sibotshiwe said other opposition leaders were also in hiding, among them Tsvangirai's campaign manager. Officials were no longer working out of the party's headquarters in Harare for fear of arrest, he said.

Tsvangirai's second in command, Tendai Biti, is jailed in Zimbabwe on treason charges, which can carry the death penalty.

Tsvangirai told Dutch national broadcaster NOS radio Tuesday that the Dutch ambassador had spoken to the Zimbabwean government and received assurances there was no threat to him. Tsvangirai said he might leave the embassy Tuesday or Wednesday, but Sibotshiwe said that could change.

"It's an unsure environment. You just never know what's going to happen tomorrow," Sibotshiwe said, adding he was concerned Mugabe would crack down even more in reaction to strong criticism from the U.N. Security Council.

Recent bloodshed widely blamed on supporters of Mugabe has killed dozens of opposition activists and other Zimbabweans.

The non-binding presidential statement was the Security Council's first formal action on Zimbabwe's political and humanitarian crises. Council members also agreed that the violence and restrictions on opposition activists imposed by the Mugabe government "have made it impossible for a free and fair election to take place" on Friday.

The 84-year-old Mugabe and United Nations Zimbabwean Ambassador Boniface Chidyausiku pledged to press ahead with Friday's vote, despite the international criticism and the lack of opposition.

Tsvangirai said the election was rigged and his supporters face too much violence for him to keep running. He won the first round of voting on March 29, but lacked an outright majority against Mugabe.

"There has been too much violence, too much intimidation," U.N. Secretary General Ban Ki-Moon told a brief news conference, and a runoff "would only deepen divisions within the country and produce a result that cannot be credible."

Ban said he was working with South Africa and the African Union to find a solution. Dumisani Kumalo, South Africa's ambassador to the U.N., told reporters that it should be left up to the Zimbabweans to decide whether to delay Friday's voting or to revert to the earlier result and consider Tsvangirai the interim president.

Most of the council's negotiations were conducted privately. Members met openly for less than a half-hour to get an update on what is happening from U.N. Undersecretary-General for Political Affairs B. Lynn Pascoe.

He said ample evidence shows Mugabe's government is waging a "widespread campaign of retaliation and threat" and spreading "fear, hostility and attacks" against its opponents.

Mugabe's government is no longer capable of holding a legitimate election, Pascoe told the council, and Mugabe's plan to push ahead with a runoff Friday "would only increase divisions and produce discredited results."

Already, tens of thousands of Zimbabweans have been uprooted from their homes and 85 people have died in election violence, human rights groups say. Tsvangirai has repeatedly been detained by police and contended with warnings of a state-sponsored assassination plot. His top deputy was arrested on treason charges that carry the death penalty.

The U.S., Britain, France and other Western powers tried but failed to include language asserting that Tsvangirai should be considered the legitimate president, until another fair election can be held.

They faced opposition mainly from South Africa and China, Zimbabwe's biggest trading partners, and from Russia, which had previously opposed discussions on Zimbabwe. The all-day discussions on the various drafts extended into the evening.