Southern African leaders held an emergency meeting today to discuss Zimbabwe's crisis and Kenya stepped up African pressure for intervention, saying the country risked a Rwanda-style disaster.
Former colonial power Britain said it was preparing tougher sanctions against specific members of Zimbabwe's government.
Zimbabwean opposition leader Morgan Tsvangirai urged the UN to isolate Mr Mugabe
Kenyan Prime Minister Raila Odinga told reporters: "Zimbabwe right now is a disaster in the making," while Foreign Minister Moses Wetangula described the crisis as a blot on Africa.
Mr Odinga, one of the continent's most outspoken critics of President Robert Mugabe, said Friday's presidential election should be postponed.
"If the world does not act now, we will soon have a situation very similar to what we saw in Rwanda," he said referring to the 1994 genocide in which 800,000 people died.
Opposition Movement for Democratic Change leader Morgan Tsvangirai, who has withdrawn from the election because of violence against his supporters, urged the United Nations to isolate Mr Mugabe and called for a peacekeeping force. He accused Mr Mugabe, (84), of declaring war.
Mr Tsvangirai has said Zimbabwe would "break" if the world did not come to its aid. This afternoon, the MDC leader left the Dutch embassy in the capital Harare where he had sought refuge since Sunday. He has since returned after giving a press conference at his home.
Mr Mugabe has refused to call off the vote, shrugging off mounting international pressure including Monday's unprecedented UN Security Council condemnation of violence, which said a free and fair run-off election on Friday was impossible.
Leaders of a Southern African Development Community (SADC) security grouping of Tanzania, Angola and Swaziland today started a meeting near the Swaziland capital Mbabane. But the region's designated mediator, South African President Thabo Mbeki, would not attend, his spokesman said.
Tanzanian President Jakaya Kikwete, Swaziland's King Mswati III and SADC executive secretary Tomaz Augusto Salomao were at the meeting. Angolan President Jose Eduardo dos Santos, who has called on Mr Mugabe to act to end the election violence, was not present.
The Tanzanian government said Mr Mbeki had been invited. The South African president has been negotiating between Mr Mugabe and Zimbabwe's opposition since last year but has been widely criticised for being ineffective and too soft on Mr Mugabe.
Mr Odinga suggested a team from the African Union, backed by the United Nations, should be involved in the crisis which has seen the collapse of Zimbabwe's economy - now suffering hyperinflation of around 2 million per cent according to experts.
The Movement for Democratic Change (MDC) said today that armed police had cordoned off and raided its office in the eastern city of Mutare. Nobody was arrested.
There has been wide international condemnation of the violence but SADC is seen as the only body that can influence events in Zimbabwe. Several of its members have been flooded by millions of refugees fleeing the economic collapse of the once prosperous country.
Britain has been heavily critical of Mr Mugabe, but has little influence over Zimbabwe. Prime Minister Gordon Brown said tougher sanctions were being prepared against members of Mr Mugabe's government.
"We are preparing intensified sanctions, financial and travel sanctions, against named members of the Mugabe regime," Mr Brown told the House of Commons. He said Britain would also try to ensure Zimbabwe's cricket team does not tour England next year.
Development ministers from ten countries, including the US, Britain, Japan, France and Switzerland, said in a statement that they encouraged the growing concern about Zimbabwe among African countries but the southern African region must do more to put pressure on Mr Mugabe.
Nobel laureate Archbiship Desmond Tutu also called for peacekeepers to be sent to Zimbabwe. Mr Mugabe "has mutated into something quite unbelievable. He has really turned into a kind of Frankenstein for his people," Dr Tutu told ABC television in Australia