Responding to a chorus of international criticism of Zimbabwe's long delay in issuing results of the March 29 vote, Justice Minister Patrick Chinamasa accused Tsvangirai -- who says he defeated Mugabe in the election -- of being a British puppet.

At a summit of the United Nations and African Union on Wednesday, British Prime Minister Gordon Brown said: "No one thinks, having seen the results of polling stations, that President Mugabe has won."

Chinamasa responded: "It is clear from the correspondence that Tsvangirai along with Brown are seeking regime change in Zimbabwe, and on the part of Tsvangirai, this is treasonous."

He added in a statement in state media: "There is no doubting the consequences for acting in a treasonous manner."

Tsvangirai's Movement for Democratic Change (MDC) accuses Mugabe of organising a violent militia crackdown to help him steal the March 29 elections, in which his ZANU-PF party lost control of parliament for the first time in his 28-year rule.

No official results have been released from the presidential vote which has been embroiled in a series of legal cases.

The Group of Eight advanced nations were the latest to join the international criticism on Thursday, expressing "deep concern" about rising tension in Zimbabwe.

G8 foreign ministers urged a "speedy, credible and genuinely democratic resolution" to the situation and a swift release of the results, according to a statement released by this year's group host, Japan.

"They stress that violence and intimidation must have no place in this process," a statement added.

FAIR OUTCOME

Brown was speaking at a summit in New York where Western states and the United Nations urged action to ensure a fair outcome from the Zimbabwe election.

But African countries avoided the issue and Security Council president South Africa opposed discussion of Zimbabwe. President Thabo Mbeki is under increasing criticism at home for insisting on a soft approach of quiet diplomacy in Zimbabwe.

Chinamasa accused Brown of taking a hard line to promote British interests, undermine Zimbabwe's electoral processes and mislead the international community.

"We tell him (Brown) clearly and without ambiguity that we are not a colony of the British," said Chinamasa, repeating a frequent line by Mugabe who paints London, not Tsvangirai as his real opponent.

Zimbabwe's economy is in ruins, with 80 percent unemployment, chronic food shortages and the world's worst inflation rate of almost 165,000 percent. Mugabe is widely blamed for the collapse and critics say the country's misery will only end when he is replaced.

Trying to counter accusations at home that he is taking too soft a line on Zimbabwe, Mbeki told reporters after the summit the only way for mediators to resolve the impasse was to keep talking with both Mugabe's government and the opposition.

A defensive Mbeki conceded at a news conference in New York there were "things that have gone wrong" in Zimbabwe and said opposition parties must be able to participate in verifying the election results.

U.N. Secretary-General Ban Ki-moon indicated to the gathering he was not satisfied with a soft approach.

"The Zimbabwean authorities and the countries of the region have insisted that these matters are for the region to resolve but the international community continues to watch and wait for decisive action," Ban said.

"A stolen election would not be a democratic election at all," Brown told the summit. "Let a single clear message go out from here in New York that we ... stand solidly behind democracy and human rights for Zimbabwe."