( Reuter )- Riot police patrols appeared on the streets of Zimbabwe's capital on Sunday after a long delay to election results fuelled suspicions that President Robert Mugabe may try to cling to power by rigging the vote.
Reuters journalists saw the riot police on the streets of Harare. Residents in poor outlying townships said they had also seen stepped-up patrols.
"They are here and we have been told to stay indoors," a resident in the eastern suburb of Tafara said.
Mugabe faced the biggest challenge of his 28-year-rule in Saturday's election with Zimbabwe's economic collapse and a two-pronged opposition attack putting him under unprecedented pressure.
The opposition MDC party led by Morgan Tsvangirai said it had won an overwhelming victory, but the electoral commission said no results would be released until 6 a.m. ( 5 a.m. British time) on Monday, 35 hours after polls closed.
Results in previous votes have begun emerging soon after the election ended.
" Mugabe has lost the election. Everyone knows no one voted for Mugabe , but they are now trying to cook up a result in his favour , " said MDC Secretary-General Tendai Biti .
"Morgan Tsvangirai is the winner, period."
Two South African members of a regional observer mission also said the delay "underscores the fear that vote rigging is taking place."
The two South Africans refused to sign a positive preliminary report on the elections by the Southern African Development Community (SADC). They said there was evidence of "widespread and convincing" MDC victories.
Mugabe's government warned the opposition it would regard victory claims as a coup attempt.
SADC mission chairman Jose Marcos Barrica of Angola told reporters through an interpreter the election "has been a peaceful and credible expression of the will of the people of Zimbabwe."
Mugabe , in power for 28 years, is being challenged by veteran rival Tsvangirai and ruling ZANU-PF party defector Simba Makoni , who both accuse the former guerrilla leader of wrecking a once prosperous economy and reducing the population to misery.
Although the odds seem stacked against Mugabe , 84, analysts believe his iron grip on the country and backing from the armed forces will enable him to declare victory.
Barrica expressed concern about the voters roll, opposition access to the media and statements by the heads of security forces who had said they would not accept an opposition victory.
But he added: "We saw that the basic conditions for a free and fair election were there."
The dissenting mission members from South Africa's opposition Democratic Alliance (DA), said in a statement: "It is impossible for this deeply flawed electoral process to be viewed as a credible expression of the will of the people of Zimbabwe."
SADC, which critics say has been too soft on Mugabe , has unsuccessfully tried to mediate an end to Zimbabwe's crisis, which has turned a quarter of the population into refugees.
Electoral officials said the delay was caused by the complexity of counting in presidential, parliamentary and local polls and the need to verify results meticulously.
Zimbabwe's security forces, which have thrown their backing firmly behind Mugabe , said before the election they would not allow a victory declaration before counting was complete.
Government spokesman George Charamba warned the opposition against such claims. "It is called a coup d'etat and we all know how coups are handled," he told the state-owned Sunday Mail.
Residents in the eastern opposition stronghold of Manicaland said riot police stopped a victory demonstration by about 200 MDC supporters on Sunday. There was no violence, they said.
The United States said it was worried by the conduct of the election and the absence of most international observers.
"The Mugabe regime is a disgrace to the people of Zimbabwe and a disgrace to southern Africa and to the continent of Africa as a whole," Secretary of State Condoleezza Rice told reporters during a visit to Jerusalem.
Zimbabwe is suffering from the world's highest inflation rate of more than 100,000 percent, chronic shortages of food and fuel, and an HIV/AIDS epidemic that has contributed to a steep decline in life expectancy.
Mugabe accuses the West of sabotaging Zimbabwe's economy. He rejected vote-rigging allegations.