"There is no agreement in there (in the talks), and that is what you are going to hear soon," the source close to the talks told Reuters.
Former South African President Thabo Mbeki said earlier was confident the emergency regional meeting would salvage the power-sharing agreement between Zimbabwean President Robert Mugabe and the MDC opposition.
The Southern African Development Community (SADC) convened the meeting amid fears the Sept. 15 deal was about to unravel after weeks of fruitless negotiations between ZANU-PF and two Movement for Democratic Change factions.
The accord is seen as key to any effort to pull Zimbabwe out of a deep economic crisis. Inflation is out of control and food and fuel shortages are widespread in the once prosperous nation.
Tsvangirai defeated Mugabe in a presidential election on March 29 but by too few votes to avoid a run-off in June. Mugabe won the second round after Tsvangirai pulled out, saying his supporters had been subjected to violence and intimidation.
Mugabe, Tsvangirai and Arthur Mutambara, the leader of a small MDC faction, signed an agreement to form a unity government last month after mediation by Mbeki. The parties then locked horns over control of ministries.
Mbeki and the leaders of Mozambique, Angola, Swaziland and South Africa held talks with Mugabe, Tsvangirai and Mutambara.
Tsvangirai, set to become prime minister, accuses ZANU-PF of trying to make the MDC a junior partner with responsibility for lesser ministries. He boycotted a summit in Swaziland last week, saying Mugabe’s government refused to give him a passport.
In turn, ZANU-PF accuses Tsvangirai of wanting to seize power rather than share it and of stalling the talks to try to drag in the United Nations to mediate.