Harare/Johannesburg - Southern African heads of state converged on South Africa' capital Pretoria Monday, in yet another attempt to eke a compromise from elderly Zimbabwean President Robert Mugabe and the country's opposition on a power-sharing agreement.

Monday's extraordinary summit of the 15-nation Southern African Development Community (SADC), which is being chaired by South African president and current SADC chairman Kgalema Motlanthe, is the bloc's third crisis summit on Zimbabwe in under a year.

At the last two such summits Mugabe's peers studiously avoided condemning Zimbabwe's authoritarian leader, giving him rein to hang onto power despite being defeated by the opposition in last year's elections.

Monday's summit will focus on the four-month standoff between Mugabe's Zanu-PF and Morgan Tsvangirai's Movement for Democratic Change (MDC) on power-sharing.

The two leaders signed an accord in September to form a unity government, with Mugabe as president and Tsvangirai as prime minister.

But the MDC has gone cold on the deal, after Mugabe insisted on retaining all the most important portfolios, bar finance, for Zanu-PF. A renewed state crackdown on opposition supporters, dozens of whom have been detained, disappeared for weeks on end and allegedly tortured, has further poisoned relations between the parties.

As the Zimbabwean crisis starts to contaminate life beyond its borders, pressure is growing on SADC to end its support for Mugabe.

At least 33 people have died of cholera in South Africa in recent months as sick, hungry Zimbabweans stream across the border. Zimbabwe's own death toll is close to
3,000 since August, when the outbreak began in crowded townships.

Tsvangirai has refused to work with Mugabe until positions of power are equitably distributed and detained activists are released.

Zanu-PF and SADC are trying to convince the MDC into joining the government and leaving disagreements for later. (dpa)