Zimbabwe's main opposition party claimed today to be heading to a clear victory over Robert Mugabe after presidential and parliamentary elections.

Official results from Saturday's election only trickled out, however, prompting accusations that the veteran President was trying to fix the poll results in a desperate bid to cling to power.

With 24 of the 210 parliamentary seats so far declared by the Zimbabwe Electoral Commission, Mr Mugabe's Zanu-PF was level-pegging with the opposition Movement for Democratic Change (MDC), led by Morgan Tsvangirai, on 12 seats each.

No official figures were given for the presidential contest.

The MDC, using results posted outside polling booths around the country, said today that it enjoyed a clear lead. Its secretary-general, Tendai Biti, told a news conference: "From the 128 constituencies whose results we have calculated so far, we have 96 out of the 128 seats and Morgan Tsvangirai is at 60 per cent, Robert Mugabe is at 30 per cent."

Among the notable early results announced by the election commission was a defeat for Patrick Chinamasa, the Justice Minister, in the rural eastern constituency of Makoni Central.

But the slow pace of announcements led to fears that Mr Mugabe, who has ruled since independence from Britain in 1980, was hoping to rig the election — as he has been accused of doing in the past.

In some previous elections, initial results were known within hours of polls closing. "Clearly the delay is fuelling speculation that something might be going on," said Noel Kututwa, chairman of the Zimbabwe Electoral Support Network, which includes 38 civic, church and other groups.

In London, David Miliband, the Foreign Secretary, said that there should be "no unnecessary delay" in releasing the full results.

"The next few days are critical for the future of Zimbabwe," Mr Miliband said in a statement. "On Saturday, the Zimbabwean people turned out to vote in their millions. Their voice must now be heard without delay.

He added: "It is vital that this election should chart a course for Zimbabwe chosen by the people of Zimbabwe. As part of that expression of the popular will, civil society activists in Zimbabwe have been monitoring the elections and we look forward to their account.

"There must be no unnecessary delay in the publication of the official results. The international community is watching events closely, and the Prime Minister and I will be speaking today to international leaders, particularly those from Southern Africa."

Mr Biti criticised a preliminary endorsement of the polling by a South African Development Community (SADC) observer mission, describing it as "an attempt to sanitise what is not a free and fair election".

The SADC mission chairman, José Marcos Barrica, of Angola, told reporters that the election had been a "peaceful and credible expression of the will of the people".

Two South African members of his mission refused to sign its preliminary report, however, complaining that the delay in announcing the election results "underscores the fear that vote-rigging is taking place".

Voting in Saturday’s elections — which presented Mr Mugabe, 84, with the toughest challenge ever to his 28-year rule — was generally peaceful. The election hinged largely on the destroyed economy, with inflation soaring beyond 100,000 per cent.

Running against Mr Mugabe was Mr Tsvangirai, 55, who narrowly lost disputed 2002 elections, and the former ruling party loyalist and finance minister Simba Makoni, 58. If no presidential candidate wins 50 per cent plus one vote, there will be a run-off.

Security and government officials loyal to Mr Mugabe have warned Mr Tsvangirai against declaring a victory. "It is called a coup d’etat and we all know how coups are handled," George Charamba, the chief presidential spokesman, was quoted as saying in the state-controlled Sunday Mail newspaper.

Sources within the ruling party said that Mr Mugabe was consulting with his security chiefs last night amid fears of how they might react to any news of his defeat. The chiefs all have said they would serve only Mr Mugabe.

But the head of the Pan-African Parliament observer mission said that the delay was creating "anxiety", and warned of a scenario similar to Kenya, where a delayed announcement of results from elections in December so rigged that no one knows who won, led to a spontaneous explosion of violence. More than 1,000 people were killed.

"These are the delays that start causing problems," Marwick Khumalo, the head of the Pan-African Parliament observers, said, adding that he was sure the electoral commission knew most results.

Earlier, people celebrated in the streets, dancing, singing and giving each other the open-handed wave that is the opposition party’s symbol. Mr Mugabe’s is a clenched fist.

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