Zimbabwe's opposition appealed Saturday for the United Nations to intervene to prevent bloodshed in a presidential runoff campaign because it fears President Robert Mugabe will use brute force to try to retain power. The appeal came as a lawyer for Zimbabwe's opposition said armed police prevented anyone from entering Zimbabwe's High Court for an opposition legal bid to have the results of the March 29 presidential election published. Alec Muchadehama said police were commanded by a senior officer wearing a shirt of the ruling Zanu-PF party. Muchadehama said no one was allowed into court and that officials said they were going to call in riot police. Members of the opposition Movement for Democratic Change (MDC) wanted to lodge an urgent suit with the High Court to force the electoral commission to publish the results. On Friday, the ruling ZANU-PF party announced it was endorsing Mugabe, whose 28-year rule led Zimbabwe from liberation to ruin, to contest a runoff election despite humiliating electoral losses. Nelson Chamisa, spokesman for Morgan Tsvangirai's MDC, said there were signals that Mugabe, 84, was preparing to crack down. Feared veterans of the guerrilla war used in the past to beat up opponents held an intimidating march Friday; opposition party offices were raided and armed police in full riot gear arrested foreign journalists in a show of force. "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 told The Associated Press. "But we cannot be alone. We need the international community to help us. The UN 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." The ZANU-PF announcement, pre-empting results from the ostensibly independent election commission, underlines that Mugabe's party is Zimbabwe's most powerful authority. Independent projections show Tsvangirai won most votes but not the 50 percent plus one needed for an outright victory. Chamisa said the party expected the High Court to hear an urgent suit to force the electoral commission to publish results of the March 29 presidential election at noon (1000 GMT). He said he expected the court to answer the petition immediately, but 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. Scores of people were killed in those campaigns. The US and other Western nations also have been pressing for the presidential results to be announced. Mugabe has ruled since his guerrilla army helped bring about an independent Zimbabwe in 1980, but his popularity has been battered by an economic slide that followed the often-violent seizures of white-owned commercial farms since 2000 that has this former food exporting nation dependent on international handouts. A third of the population have fled the country and 80 percent is jobless. With inflation raging at more than 100,000 percent, authorities introduced a new bank note denominated at 50 million Zimbabwe dollars Friday. It's worth $1 (64 euro cents) on the widely used black market and buys just three loaves of bread. The election commission continued its trickle of results Friday in races for the 60 elected Senate seats, with the opposition winning 23 to the ruling party's 20. Results on Wednesday showed Mugabe's party losing control of the lower House Assembly. 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. "There was no evidence in support of voting irregularities," Kabbah said upon arriving in Sierra Leone's capital, Freetown. Kabbah praised Mugabe as "a patriot," and said during a meeting Thursday that the Zimbabwe leader was "relaxed" despite his setback at the polls. Zimbabwe state television Friday night aired footage of their meeting, with Mugabe telling Kabbah "We don't cheat, but the other side - the forgeries!" That apparently was to back up charges made earlier Friday by Didymus Mutasa, a Cabinet minister and ZANU-PF administrative secretary, that the opposition had bribed electoral officials. Mutasa said his party would contest results for 16 House of Assembly seats. Chamisa denied the charges as "hogwash." Mutasa also accused the opposition of promising to return land to white farmers. "We are not reversing the land reform - they will get the shock of their lives," Mutasa said. The opposition leader has promised an equitable distribution of land to people who know how to farm. Mugabe claimed his land reform was to benefit poor blacks, but gave most seized farms to relatives, friends and cronies, and agricultural production has plunged. Mutasa spoke after a five-hour meeting of the party politburo, which includes eight Cabinet minister defeated the elections. Before the meeting, war veterans marched in an intimidating silent parade through downtown Harare. Their leader, Jabulani Sibanda, sounded a combative note, saying ZANU-PF lost the elections because "people were pushed by hunger and illegal sanctions," echoing a theme of Mugabe's campaign. Mugabe also appears to have the support of the security chiefs, though diplomats have reported rifts within their highly politicized upper echelons. Tsvangirai tried Thursday to reassure security chiefs who vowed a week ago to serve no one 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 person, who requested anonymity because of the issue's sensitivity. 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 US-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.