Updated

Hundreds of veterans of Zimbabwe's guerrilla war for black rule marched through the capital Friday, silent but leaving little doubt they were out to intimidate President Robert Mugabe's political opponents.

In other signs Mugabe planned to brazen out a democratic challenge to his 28 years of rule, intruders ransacked offices of the main opposition party and police detained foreign journalists overnight.

Mugabe's embattled ZANU-PF party held a strategy session Friday, its first since it lost control of parliament in weekend elections. The opposition also claimed to have won the presidency in Saturday's vote, but official presidential elections returns have not yet been released.

The meeting of the ruling party's 49-member politburo, including eight Cabinet ministers defeated in the elections, got under way about midday at party headquarters in downtown Harare. A row of luxury cars was parked outside. Journalists were barred from the building.

Police escorted about 400 war veterans as they paraded silently through downtown Harare. The feared veterans in the bush war that helped end white minority rule often are used to intimidate opposition supporters and spearheaded the often violent takeover of white farms in recent years.

Lovemore Madhuku, long an outspoken critic of the Mugabe regime, urged Zimbabweans to "defend their vote" at a news conference Friday. Madhuku heads the National Constitutional Assembly, an independent group calling for constitutional reforms and an end to human rights abuses in Zimbabwe.

Madhuku, who in the past has suffered police beatings and an arson attack on his home, called on Zimbabweans "not to give in to any form of intimidation, any form of violence ... that would be used to stop change or to steal the vote."

The opposition said it was ready to go to court to force the Zimbabwe Electoral Commission to release results, pointing out that the law gives the election commission one week to release all results.

"So we want to see results by today. If that doesn't happen then we will retrieve all our tools including court process to make sure we give Zimbabweans the results as soon as possible," said Nelson Chamisa, spokesman for the main opposition Movement for Democratic Change.

The Movement for Democratic Change asserts its leader, Morgan Tsvangirai, won the presidency outright, but said it is prepared to compete in a runoff. Independent monitors polls show Tsvangirai won the most votes, but not the 50 percent plus on vote needed to avoid a second tour.

The opposition has been weakened by internal divisions. But Friday, a splinter faction said divisions weren't an issue should there be a runoff.

"Our main motive is to support all forces against Robert Mugabe. Whatever formation is there to remove Mugabe, we are there to support it," said Abednico Bhebhe, spokesman for the Arthur Mutambara faction of the MDC.

The law requires a runoff within 21 days of the first round. 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.

MDC secretary-general Tendai Biti said hotel rooms used as offices by the opposition at a Harare hotel were ransacked Thursday by intruders he believed were either police or agents of the feared Central Intelligence Organization.

"Mugabe has started a crackdown," Biti told The Associated Press.

Biti said Tsvangirai was "safe" but had canceled plans for a news conference. Tsvangirai was arrested and severely beaten by police a year ago after a banned opposition rally.

Tsvangirai tried earlier Thursday to reassure security chiefs who vowed a week ago not to serve anyone but Mugabe, according to a person close to the opposition leader. But an agreed meeting with seven generals was canceled when the officers said that they had been ordered not to attend and that they would be under surveillance, according to the man, who requested anonymity because of the issue's sensitivity. He gave The Associated Press a copy of a letter signed by Tsvangirai and given to the generals outlining "MDC guarantees to the uniformed forces of Zimbabwe."

The letter promises generous retirement packages for those unwilling to serve an MDC government. It also promises not to take back farms given to officers under Mugabe's land reform program, except in cases in which an officer got several farms or if the land was being neglected.

It was not clear who barred the generals from the meeting. There have been reports of rifts within the highly politicized upper echelons of Zimbabwe's security forces.

The journalists, meanwhile, were detained by heavily armed riot police who surrounded and entered a Harare hotel frequented by foreign reporters and took five people away, lawyers said. The government had rejected most foreign journalists' applications to cover the elections, and had barred Western election observers.

Zimbabwe lawyer Beatrice Mtetwa said two of those detained were jailed overnight and told they would be charged Friday with practicing journalism without licenses. She said the other three were released.

The U.S.-based National Democratic Institute said one of its staff was detained by authorities at Harare's airport as he tried to leave the country Thursday. Dileepan Sivapathasundaram, a U.S. citizen, had been working with local non-governmental organizations monitoring elections.

U.S. President George W. Bush's national security spokesman, Gordon Johndroe, said Friday that White House officials were "troubled by reports we are hearing on the ground in Zimbabwe."

"Journalists and NGOs should be permitted to do their work," Johndroe said.

Mugabe has ruled since his guerrilla army helped force an end to white minority rule and bring about an independent Zimbabwe in 1980, but his popularity has been battered by an economic freefall that followed the often-violent seizures of white-owned commercial farms in 2000.

Zimbabwean authorities on Friday introduced a new 50-million bank note, state media reported. The new Zimbabwe dollar note is worth US$1 (about 60 euro cents) at the widely used black market trading and can buy just three loaves of bread. It was the third time in three months that the nation's central bank issued a higher denomination note in response to record inflation.