After weeks of violence, Zimbabwean opposition leader Morgan Tsvangirai has announced that he is pulling out of Friday's presidential election run-off, fearing massacres of his supporters and a rigged poll outcome.
The decision will be controversial, as it effectively hands victory to Robert Mugabe and his Zanu-PF party. Tsvangirai appealed to the international community to prevent a "genocide" in his country.
Civil society groups and churches say that an African and United Nations intervention is now needed.
Zanu-PF says that the election on 27 June 2008 will go ahead "with or without Mr Tsvangirai... this is not his election, not Britain's; it is a matter for the Zimbabwe constitution."
Researchers, journalists and human rights monitors say that some 3,000 people have been injured and around 100 killed in waves of violence unleashed by thuggish supporters of Mr Mugabe -- many of them secretly filmed despite attempts by the military and the security services to clamp down on free reporting.
Some 200,000 people have been forced from their homes by ruling party militias, says the BBC, which is officially banned from the country.
South African President Thabo Mbeki made another ritual appeal for "the country's leaders to get together" this evening, but observers say that a democratic resolution now looks remote.
Many Mugabe opponents will be angry with Tsvangirai's pull-out, claiming that it will give political victory and a propaganda coup to the ruling dictator, whose spokesperson immediately declared that the decision was motivated by fear of "humiliation" at the hands of voters.
The Movement for Democratic Change said that its supporters faced death threats.
President Mugabe last week said that MDC was "treasonous" and would "never" rule Zimbabwe. "God appointed me and only God can remove me", he declared, in a statement which church opponents dubbed "blasphemous".