Robert Mugabe's 28-year grip on Zimbabwe slackened dramatically last night as his party lost control of the African nation's parliament.

The opposition Movement for Democratic Change (MDC) said its leader Morgan Tsvangirai had won the presidential election, although Mr Mugabe's Zanu-PF said this was "wishful thinking".

Official figures said the mainstream MDC had taken 105 seats, a breakaway faction nine seats and an independent one in the 210-seat parliament. Zanu-PF had so far taken 94.

The official presidential election results have not yet been declared but independent observers said all the signs are that Mr Mugabe is in the most precarious position of his near-three decades at Zimbabwe's helm.

Mr Mugabe, 84, faced an unprecedented challenge in the poll after being widely blamed for the economic collapse of the once prosperous nation which the former guerrilla leader has ruled since independence from Britain in 1980.

The MDC released its own presidential results to back up its claim of victory in the presidential poll. MDC Party Secretary, General Tendai Biti, said leader Morgan Tsvangirai won 50.3% of the vote to Mr Mugabe's 43.8%, so avoiding a run-off.

Mr Biti said there was "anxiety and disappointment" at the failure of the Zimbabwe Election Commission to declare presidential results and appealed to Mr Mugabe to concede defeat and avoid "embarrassment".

But the government called the MDC claim "mischievous".

Prime Minister Gordon Brown said it was essential that the Zimbabwean people were granted the "democratic outcome" for which they voted.

The White House urged Zimbabwe's government to respect the will of the people and called on the commission to issue election results, saying: "It's clear the people of Zimbabwe have voted for change."

Mr Biti said that if the election commission decided that neither of the main candidates had won outright, the MDC would be prepared to take part in a second round.

Deputy Information Minister Bright Matonga said the claim of victory was irresponsible and could incite violence.

He said the pattern of results from the parliamentary election suggested that there would be a second round in the presidential election.

Mr Matonga added that the delay in officially declaring the result was due to the complexity of the process, with 75% of voters living in rural areas.

"President Mugabe is going nowhere. We are not going to be pressurised into anything," he said. "No-one is panicking around President Mugabe. The army is very solidly behind our President, the police force too."

Mr Mugabe, known for his fierce rhetoric, has not been seen in public since voting.

The government appears to have been preparing the population for a run-off by revealing its own projections, showing a second round would be required.

Both Mr Tsvangirai and the government have dismissed widespread speculation that the MDC was negotiating with Zanu-PF for a managed exit for Mr Mugabe.

The opposition and international observers said Mugabe rigged the last poll, in 2002. But some analysts say the groundswell of discontent is too great for him to fix the result without risking unrest.

Apart from surreal inflation of more than 100,000% and a virtually worthless currency, Zimbabweans are suffering food and fuel shortages and an HIV/Aids epidemic that has contributed to a steep drop in life expectancy.