Zimbabwe's opposition were in contact with senior military and intelligence officials last night to persuade them to respect the results of the election as pressure grew on Robert Mugabe, the president, to recognise defeat.

Sources in the opposition Movement for Democratic Change said the contacts were aimed at winning the security establishment's support or, at the least, ensuring it did not intervene to overturn what appeared to be a clear victory for Morgan Tsvangirai over Mugabe.

Tsvangirai said last night the MDC would release its final results today confirming his victory and he called on the government's electoral commission to respect the will of the people by immediately releasing the official presidential results.

"There is no way the MDC will enter into any deal before [the electoral commission] has announced the official results," he said at a press conference in Harare. "Our country is on the precipice, on the cliff edge, as we wait."

Tsvangirai said there would be no negotiations with Mugabe until after the results were released, but MDC officials confirmed there have been high-level contacts with elements of the ruling Zanu-PF party and the security institutions.

But as much-delayed results continued to trickle in from the election commission amid allegations that it is manipulating the count, Zanu-PF remained defiant.

It conceded that Mugabe may not have won an outright victory but said he would win a run-off election if no candidate won more than 50% of the vote.

The MDC's secretary general, Tendai Biti, dismissed as "complete rubbish" a BBC report that they were close to a deal that would see Mugabe step down.

On Monday, Tsvangirai approached the former army chief Solomon Mujuru, who is still a powerful figure within the military, to say the MDC was prepared to discuss the security establishment's concerns and reassure it that a transfer of power would not lead to prosecutions for past crimes or a purge.

That contact has now broadened. The MDC is also reaching out to elements of Zanu-PF through a third presidential candidate, Simba Makoni, a former finance minister who broke with the president but still has party support.

The sources said they did not believe that the officials were negotiating on behalf of Mugabe, who has previously said the opposition would never govern Zimbabwe.

But the opposition calculates that winning support within the military for respecting the election results would make it considerably harder for Mugabe to cling to power.

The MDC also reached out to more moderate elements of Zanu-PF, including members of parliament with whom it has had a working relationship.

A knowledgeable party source said the contacts were evidence that support for Mugabe within Zanu-PF was beginning to erode in the face of defeat.

"Mugabe and some of those around him decided to try and brazen it out by fixing the results," said the source.

"But Zanu-PF is not united. It has taken a big blow that it didn't expect and there are important people who recognise that they cannot go against the will of the people. They are shocked and do not have the spirit to go down fighting for Mugabe."

Mugabe's security cabinet of senior security and party officials decided on Sunday night not to recognise defeat in the presidential and parliamentary vote, and that the electoral commission - which was withholding the results - should fix them to deny Tsvangirai victory.

MDC officials said the accounts they received of the tone of that meeting hours later had the party worried that the government might cancel the election and arrest opposition leaders, or that the military might intervene.

Before the election the army chief, Constantine Chiwenga, said he would not recognise an MDC victory but the opposition said other officers were not prepared to go against the will of the people and prop up a defeated government that has no apparent strategy to rescue the country from hyperinflation, food shortages and deepening poverty.

The military leadership must also be concerned about the loyalty of ordinary soldiers, many of whom will have voted for the opposition because they can barely feed their families.

The election commission began releasing results the morning after the security cabinet meeting although only piecemeal for the lower house.

Of the 132 seats declared so far, Zanu-PF had won 64 and the MDC 62.

Six others went to a breakaway faction of the MDC. Three government ministers have lost their seats.

But Zanu-PF had a substantial lead in the total number of votes cast - 480,000 to 400,000 for the MDC from the first 90 seats - leading the opposition to conclude that the electoral commission is gradually loading the count in favour of Mugabe.

No presidential results have been released.

However, overturning the opposition's victory through fraud would be difficult and Zanu-PF officials conceded Mugabe may not have won an outright victory.

The MDC say its calculations give it 60% of the presidential vote to 30% for Mugabe. Independent poll monitors give Tsvangirai between 50% and 55%.

But the party's election strategists said they were prepared for a run-off if necessary and they believed Tsvangirai would win with the support of ousted opposition candidates.