By Cris Chinaka

HARARE, April 1 (Reuters) - Riot police in armoured carriers patrolled two of Harare's opposition strongholds on Tuesday as suspicions grew that President Robert Mugabe was rigging Zimbabwe's most important election since independence.

A resident of one of the townships said a convoy of riot police in about 20 vehicles moved through the vast area. "There are a lot of patrols here," said the resident, adding people had been told to stay off the normally teeming streets. Three days after the vote, only 89 of 210 parliamentary constituencies had been declared, showing the ruling ZANU-PF two seats ahead of the main opposition Movement for Democratic Change (MDC).

Justice Minister Patrick Chinamasa, one of Mugabe's closest allies, and the public affairs minister lost their seats.

No results have been announced for the presidential vote, in which Mugabe faces the most formidable political challenge of his 28 years in power.

The opposition has accused the veteran leader of delaying the issuing of the results in a bid to steal the election, which Zimbabweans hoped would ease daily hardships.

Zimbabweans are suffering the world's highest inflation of more than 100,000 percent, food and fuel shortages, and an HIV/AIDS epidemic that has contributed to a steep decline in life expectancy.

"It is now clear that there is something fishy. The whole thing is suspicious and totally unacceptable," MDC spokesman Nelson Chamisa said.

Mugabe has denied rigging the election and his government warned that any early victory claim would be regarded as an attempted coup.

An independent Zimbabwean election monitoring group forecast Morgan Tsvangirai, leader of the largest faction of the MDC, would win the most votes in the presidential poll but not by a big enough margin to avoid a second round.

The Zimbabwe Election Support Network (ZESN) said its projections giving him 49.4 percent. It predicted Mugabe would win 41.8 percent and ruling ZANU-PF party defector Simba Makoni would get 8.2 percent.

Seven European countries and the United States called on Zimbabwe's Electoral Commission to quickly release the results.

Electoral Commission chairman George Chiweshe said the slow pace was due to the complexity of holding presidential, parliamentary and local polls together for the first time.

"FAIR AND CREDIBLE"

Mugabe, 84, is under unprecedented pressure from a two-pronged attack by veteran MDC rival Tsvangirai and Makoni, who both blame him for Zimbabwe's ruin.

And although the odds seemed stacked against Mugabe, in power since independence in 1980, analysts believe his iron grip on the country and solid backing from the armed forces could enable him to ignore the results and declare victory.

Marwick Khumalo, head of an observer group from the Pan-African parliament, said the elections themselves were free, fair and credible overall.

Official results so far showed ZANU-PF with 43 seats, MDC with 41 and a breakaway MDC faction with five. Five of the new seats the MDC won were from traditional ZANU-PF strongholds.

The MDC said unofficial tallies showed Tsvangirai had 60 percent of the presidential vote, twice the total for Mugabe. Private polling organisations also put Tsvangirai ahead.

"In our view, as we stated before, we cannot see the national trend changing. This means the people have spoken, they've spoken against the dictatorship," MDC Secretary-General Tendai Biti said. (Additional reporting by Stella Mapenzauswa, Nelson Banya and Muchena Zigomo, Paul Taylor in Brussels, by Tabassum Zakaria in Washington and Adrian Croft in London; James Mackenzie in Paris; editing by Michael Georgy and Dominic Evans) (For full Reuters Africa coverage and to have your say on the top issues, visit: http://africa.reuters.com)

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