(AP) Zimbabwe's opposition leader says he fears that President Robert Mugabe is preparing a "war against the people" in an attempt to hold on to power.
Movement for Democratic Change leader Morgan Tsvangirai has told a news conference that his party is reluctant to take part in an election runoff because of the growing risks of violence.
Earlier today, armed police prevented opposition lawyers from entering Zimbabwe's High Court to lodge an urgent suit aiming to force the publication of presidential election results.
Opposition lawyer Alec Muchadehama said a senior police officer wearing a ruling ZANU-PF shirt gave the orders, amid increasing signs of a clampdown.
"No one is going to enter. They say they are going to call the riot police," Muchadehama said. Journalists waiting outside the court also were ordered to disperse.
The Movement for Democratic Change wanted the High Court to force the electoral commission to publish results of the March 29 presidential election.
The opposition will mount a new bid in the High Court on Sunday for the election results to be published.
Official results for the parliamentary elections showed the ruling party lost its majority in the 110-seat parliament. Independent observers projected that MDC candidate Tsvangirai won most of the votes cast in the presidential contest but not enough for an outright victory over longtime ruler Robert Mugabe.
The ruling ZANU-PF party announced Friday it was endorsing Mugabe, whose 28-year rule led Zimbabwe from liberation to ruin, in a runoff election.
Earlier, the opposition asked the United Nations to intervene during the runoff campaign over fears that Mugabe, 84, may stage a violent crackdown to retain power.
London's Guardian newspaper reported that Mugabe's aides said he is prepared to give up power in return for immunity from prosecution for past crimes, but that if opposition leaders do not agree, then Mugabe may declare emergency rule.
Nelson Chamisa, spokesman for the opposition, pointed to signs of a coming clampdown, including a march in Harare by war veterans loyal to Mugabe who have beat up opponents in the past, a raid on opposition party offices and the detention of foreign journalists by armed police in full riot gear.
"They are trying to intimidate people, they are trying to set up the context for unleashing violence. The vampire instincts of this regime are definitely going to come out," Chamisa charged.
Zimbabwe needs the assistance of the international community, he said.
"The U.N. has to make sure that there is no violence in this country. ... They should not (wait to) come when there is blood in the street, blood in the villages."
But South African President Thabo Mbeki said Saturday that international intervention is not needed.
"I think it is time to wait. Let's see the outcome of the election results. If there is a re-run of the presidential election let us see what comes out of that," Mbeki said.
Mugabe has ruled since his guerrilla army helped bring about an independent Zimbabwe in 1980. His popularity has been battered by an economic slide that followed the often-violent seizures of white-owned commercial farms since 2000. A third of the population has fled the country, 80 percent of those who remain are jobless and inflation is more than 100,000 percent.
Chamisa said he expected the court to answer its petition for the election results immediately in Saturday morning's hearing, but he was not hopeful of the outcome.
Zimbabwe's courts are stacked with Mugabe sympathizers who have delayed hearing opposition challenges to results of 2002 and 2005 elections that international observers said were marked by fraud and intimidation.
The U.S. and other Western nations also have been pressing for the presidential results to be announced.
The law requires a runoff within 21 days of the first elections. But diplomats in Harare and at the United Nations said Mugabe was planning to declare a 90-day delay to give security forces time to clamp down.
An African Union election observer team found no evidence of fraud during voting last weekend, according to the delegation's leader, former Sierra Leone president Ahmed Tejan Kabbah.
Kabbah praised Mugabe as "a patriot," and said during a meeting Thursday that the Zimbabwe leader was "relaxed" despite his setback at the polls.
New York Times journalist Barry Bearak was among those detained Thursday by heavily armed riot police who surrounded and entered a Harare hotel frequented by foreign reporters, lawyers said. The U.S.-based National Democratic Institute said one of its staff, American Dileepan Sivapathasundaram, was detained at Harare's airport as he tried to leave the country Thursday.
The government had rejected most foreign journalists' applications to cover the elections and had barred Western election observers.
Lawyer Beatrice Mtetwa said the attorney general decided there was no case against the two Americans and a third person who was not identified. However, police decided to hold them. It was not clear whether new charges would be filed.
State Department Tom Casey said four Americans were detained Thursday, but two had been released and were leaving the country. He told reporters Friday that U.S. officials had been in contact with the two Americans still in custody.
© MMVIII, CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.