Preliminary talks on power sharing between Zimbabwe's ruling ZANU-PF party and the opposition Movement for Democratic Change continued Wednesday as negotiators worked on a draft memorandum of understanding setting the ground rules for talks on establishing either a government of national unity or a transitional authority.

State media had raised expectations that such a memorandum would be signed Wednesday, but reports said the MDC was digging in its heels on its key conditions for an accord.

Sources in Harare and Pretoria informed on the talks said the main sticking point was the continuation of the political violence that surged after the March 29 general and presidential elections and continued through the widely condemned June 27 presidential run-off election in which President Robert Mugabe, the only participating candidate, claimed victory.

The MDC has insisted the violence must stop before serious talks can begin.

The opposition formation headed by Morgan Tsvangirai said some 1,500 of members are in detention around the country and 20 of its elected members of parliament are in detention or in hiding for fear of state persecution. ZANU-PF is demanding that the MDC agree to ask the Western powers to lift economic and travel sanctions against President Robert Mugabe and other members of his inner circle, and has also set conditions regarding land reform.

Another outstanding issue is whether South African president Thabo Mbeki will continue as sole mediator in the talks, or whether mediation will be expanded to include an African Union envoy as Tsvangirai has demanded and others have urged. Pretoria and ZANU-PF say there is no authority for such an expansion, insisting that the African Union and the Southern African Development Community have expressed full confidence in Mr. Mbeki's mediation.

The mediation issue is expected to figure prominently on the agenda for discussions Friday when Mr. Mbeki meets with A.U. Commission Chairman Jean Ping in Durban, South Africa. Political analyst Msekiwa Makwanya told reporter Blessing Zulu of VOA's Studio 7 for Zimbabwe that any delay in the talks hurts the Zimbabwean people.

Though political violence continues in some parts of Zimbabwe, courts in a number of towns have been releasing opposition members held under charges of inciting or committing political violence. In Bindura, capital of Mashonaland Central province, the magistrate’s court granted release on bail to 50 MDC activists held since shortly after the March round of elections.

Another court in Gwanda, Matabeleland South province, released 25 others MDC members. On Monday a court in Harare released 14 opposition supporters charged with political violence saying the state should summons them at a later date if it wishes to bring them to trial.

Opposition negotiators in the crisis talks have set as one of their conditions the release of all political prisoners in addition to the cessation of political violence. The government has not acknowledged that it is holding political prisoners - but the pattern of releases suggests authorities want to establishing conditions conducive to progress in the talks.

Political analyst Farai Maguwu told reporter Jonga Kandemiiri of VOA's Studio 7 for Zimbabwe that by releasing MDC activists, the government has responded to pressure from the international community and regional leaders to show good faith in the talks.

But MDC officials point out that parliamentarian-elect Pearson Mbalekwa of Zvishavane-Ngezi constituency in Midlands province, and 15 other MDC activists, are still held in Hwange prison. A former ZANU-PF parliamentarian and Central Intelligence Organization operative, Mbalekwa broke with the government in 2005 over the forced eviction and demolition campaign that it named Operation Murambatsvina, Shona for "Drive Out the Trash." Sources said Mbalekwa spent 16 days without bathing before being transferred to the Hwange prison.