A day after long talks without conclusion, Southern African leaders planned a new summit to break Zimbabwe's political impasse.

On Monday President Robert Mugabe and rival Morgan Tsvangirai and after 12 hours of discussions, Mugabe said he had accepted a proposal from the regional Southern African Development Community (SADC) bloc that would have seen Tsvangirai sworn in as prime minister on Saturday.

However a bitter and angry Tsvangirai left the talks refusing to accept the post until crucial issues were resolved.

The leader of the Movement for Democratic Change (MDC) told the AFP, Unfortunately, there's been no progress because the very same outstanding issues on the agenda... are the same issues that are creating this impasse. For us as the MDC, this is probably the darkest day of our lives, for the whole nation is waiting.

Following the latest failure to try and implement a power-sharing deal struck between the two rivals last September, leaders of the 15-nation SADC bloc agreed to hold another Zimbabwe crisis summit next Monday.

Analysts seem gloomy about the prospects following several failed SADC interventions.