Southern African heads of state are making another attempt to resolve the political deadlock in Zimbabwe, with a special summit in South Africa.
President Robert Mugabe's Zanu-PF party and the opposition MDC have been unable to agree on a government despite signing a power-sharing deal last year.
They have been unable to agree on who should control key government posts.
Zimbabwe is in a state of economic and social collapse with nearly 3,000 deaths from a cholera epidemic.
There is scant hope that Monday's regional summit will lead to the formation of a power-sharing government in Zimbabwe, says the BBC's southern Africa correspondent Peter Biles, at the summit in South Africa's capital, Pretoria.
It is the fourth such meeting since the inconclusive elections in March 2008.
A week ago, Robert Mugabe and Morgan Tsvangirai met in Harare, and failed to resolve their differences.
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One analyst says those talks collapsed in "real acrimony".
The main issue of contention is over who controls key ministries and other top public posts. President Mugabe has said he will not compromise any further.
If there is still no agreement on Monday, he may ask the Southern African Development Community (SADC) for the legitimacy to form a new government without the MDC opposition.
The MDC's secretary general, Tendai Biti, said he did not expect the summit to resolve the impasse.
He told the BBC's Network Africa that the MDC would continue using its own methods to weaken Mr Mugabe's grip on power.
"The fact that he [Mr Mugabe] doesn't control parliament now is a proof of the fact that the methods we have been using of slow, incremental change will work. But nobody is going to push us to take up arms, we are not going to do that."
SADC - which has called this emergency summit - looks powerless and has shown no willingness to impose sanctions on Zimbabwe, says our correspondent.
South Africa's foreign minister has said any solution lies solely in the hands of Robert Mugabe and his political rivals.
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