Gordon Brown says he is “appalled” by new signs of intimidation and violence in Zimbabwe and has warned President Robert Mugabe that the world's patience is fast running out.

The Prime Minister's criticisms came a few hours after police announced a ban on political rallies in the African nation, in an attempt to subdue public unrest about suppressed presidential election results.

Mr Mugabe dismissed Mr Brown as "a little tiny dot" who could not speak for the world.

"If Brown is the world, sure, he will lose patience. I know Brown as a little tiny dot on this planet,” the 84-year-old Zimbabwean leader said.

Thabo Mbeki, the South African President, held urgent talks in Harare this morning with Mr Mugabe, who is believed to have lost the election.

Hopes of bringing international influence to bear on Zimbabwe rest with the South African leader, after Mr Mugabe pulled out of this weekend's regional summit to discuss his nation's problems.

Mr Brown had talked with Mr Mbeki last weekend in an attempt to persuade him to use his influence to end the elections stand-off. Today, in his second statement about the Zimbabwe election in 12 hours, he added: “We can’t wait any longer for the announcement of these results."

But Mr Mbeki emerged from his hour-long meeting with Mr Mugabe today to insist there was no crisis in Zimbabwe, and to call for patience: “I wouldn’t describe that as a crisis. It’s a normal electoral process in Zimbabwe. We have to wait for Zimbabwe Electoral Commission to release (the results),” he told reporters.

Ahead of the summit in Zambia, both Britain and the US condemned the use of violence by Zimbabwe security forces and supporters of the ruling Zanu-PF party.

Mr Brown said he and African leaders shared the Zimbabwean people's "demonstrated commitment" to democracy.

“I cannot understand why it is taking so long to announce the result of the presidential elections. I am appalled by the signs that the regime is once again resorting to intimidation and violence," Mr Brown said.

“We will be vigilant. The international community will remain careful to do nothing to undermine efforts to secure an outcome that reflects the democratic will of the people of Zimbabwe.

“But the international community's patience with the regime is wearing thin.”

Human rights watchdogs and Zimbabwe's opposition party the Movement for Democratic Change say Zanu-PF has unleashed a campaign against violence since losing control of parliament in the March 29 election.

The US State Department called on the Zimbabwe government to “immediately desist” from acts of violence and allow the electoral process to continue.

“These incidents appear to target individuals who voted against Zanu-PF candidates during the elections,” said Sean McCormack, State Department spokesman.

Today's meeting with Mr Mbeki - the first between the two men since the March 29 election - was a rare sign that Mr Mugabe might be willing to listen to international concerns, though South Africa and other African nations have been loath to criticise the ageing Zimbabwean leader.

Up to 10 African heads of state were expected to participate in today's Southern African Development Community (SADC)emergency summit in Lusaka. It was called by Zambian President Levy Mwanawasa, the only southern African leader who has publicly criticised Mr Mugabe's policies.

Mr Mwanawasa told the assembled leaders: “SADC can no longer continue to stand by and do nothing when one of its members is experiencing political and economic difficulties.”

But he added: “This summit is not intended to put his excellency, Robert Mugabe, in the dock. In fact it would be un-African to even make such a suggestion”

Zimbabwe opposition leader Morgan Tsvangirai also attended. He claims to have won the presidential election outright and has travelled around southern Africa in recent days asking neighbouring leaders to push for Mugabe to resign after 28 years in power.

In Botswana on Friday, Mr Tsvangirai said he was a “prime target” for security forces and feared returning home.

His party has accused security forces and ruling party militants of engaging in a wave of violence against perceived opponents to intimidate voters and ensure Mugabe wins a run-off election. It had been organising a rally for Monday, but that may be jeopardised by the ban on political demonstrations.

Militants this week invaded the country's few remaining white-owned farms, saying they were trying to protect Zimbabweans from encroaching colonialism.

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