Some members of Zimbabwe's ruling ZANU-PF party appear to be rebelling against the power-sharing deal signed with the opposition on Monday.

Sources in ZANU-PF say President Robert Mugabe held an urgent meeting with the party's politburo late Tuesday to try to win full support for the agreement.

Some party leaders argue that Mr. Mugabe and ZANU-PF negotiators made too many concessions to the opposition Movement for Democratic Change.  Leaders also are reported divided over who will have roles in Zimbabwe's new unity government.

Mr. Mugabe was scheduled to meet with MDC leaders Morgan Tsvangirai and Arthur Mutambara on Tuesday, but the meeting was postponed, and is not expected to happen Wednesday either.

Under terms of the deal, ZANU-PF is to get 15 cabinet slots in the new government, while the two opposition factions get 16.  

Mr. Mugabe will remain president and head of state, while Tsvangirai will assume the post of prime minister.

In an interview with VOA's Studio 7 Zimbabwe today, the U.S. ambassador to Zimbabwe, James McGee, said the United States is "guardedly optimistic" about the power-sharing deal.  But he added that both parties must approach it in good faith for it work.

He said the U.S. could lift targeted sanctions against Mr. Mugabe's aides and allies if the new government moves in what he called a positive direction.

The power-sharing agreement aims to end months of political deadlock stemming from disputed elections and state-sponsored attacks on opposition activists.

In an interview published by Britain's Guardian Wednesday, Tsvangirai said some senior members of Mr. Mugabe's party could be tried for the violence.  He said he does not think the president himself can be held accountable.

Mr. Mugabe has ruled Zimbabwe since independence in 1980.

Some information for this report was provided by AFP.