Harare - Zimbabwe's state media Tuesday said talks on a unity government between President Robert Mugabe and opposition leader Morgan Tsvangirai "had irretrievably collapsed" after regional mediators failed to break a four-month impasse.

The Herald, which is controlled by Mugabe's Zanu-PF party, blamed Tsvangirai for the breakdown Monday night of discussions mediated by South African and Mozambican leaders and accused him of being manipulated by Western powers.

Mugabe and Tsvangirai signed an agreement to share power in a transitional government in September, but its implementation has been held up, chiefly by the
84-year-old Mugabe's refusal to cede real power to Tsvangirai's Movement for Democratic Change (MDC).

Mugabe said Monday the day-long discussions "didn't go well," but that talks with the MDC would continue.

The impasse, which is framed by severe economic and health crises in Zimbabwe, will be taken up at an extraordinary summit of SADC heads of state, to take place on Monday in Botswana or South Africa, a senior SADC official said in Harare.

Tsvangirai, whom the deal makes prime minister, called the failure of what was regarded as a last chance of saving the power-sharing agreement, "the darkest day of our lives."

While MDC members privately expressed scepticism about the likelihood of a breakthrough at what will be the third SADC crisis summit on Zimbabwe in under a year, the party is officially backing the SADC process.

"Another SADC summit is necessary," George Sibotshiwe, Tsvangirai's spokesman told Deutsche Presse-Agentur dpa. "To convene a SADC summit is to accept that the last SADC summit (in November) did not succeed in resolving the outstanding issues."

The key sticking points remains the distribution between the parties of key posts, including ministerial portfolios, and the state's renewed crackdown on the opposition.

Dozens of MDC members and civic activists are being held on allegations of banditry aimed at toppling Mugabe's regime - allegations that have been rubbished by Zimbabwe's neighbours.

Patrick Chinamasa, Mugabe's chief negotiator, was quoted in the Herald as saying that Tsvangirai had backed away from a solution proposed by South African President Kgalema Motlanthe. South Africa has been trying to convince the MDC to go into government with Mugabe and leave any shortcomings in the deal to be ironed out later.

"The MDC's intention is to create a vacuum so they can advance their agenda to illegally and unconstitutionally remove Zanu-PF from government," Chinamasa accused.

A Kenya-style unity government had been mooted as the best way of rescuing Zimbabwe from a decade of worsening tyranny and hardship under the populist Mugabe. Over 2,200 people have died of cholera, an easily preventable disease, since August, mostly for lack of clean water. (dpa)