Zimbabwe's main opposition party on Wednesday said power sharing-talks with Robert Mugabe's party were deadlocked and called on South African President Thabo Mbeki to decide on the next step.

"There is a deadlock in the talks," Nelson Chamisa, spokesperson for the Movement for Democratic Change (MDC) led by Morgan Tsvangirai, told AFP.

This is the first time the MDC has officially admitted the talks have reached an impasse since Mbeki's bid to kick-start the negotiations last Friday failed.

"It is up to Mbeki and Sadc to decide on the way forward in this circumstance," he added.

The regional bloc Southern African Development Community (Sadc) appointed Mbeki as mediator in the Zimbabwe crisis.

The talks, which began in July, have stalled amid differences over how to share executive powers between Mugabe and Tsvangirai in a national unity government.

Mugabe (84), in power since independence in 1980, was re-elected in June in a one-man presidential runoff after Tsvangirai ? the victor in the first round ? bowed out amid widespread electoral violence.