The United States has expressed skepticism over the agreement under which Zimbabwean opposition leader Morgan Tsvangirai is to join a unity government with President Robert Mugabe. U.S. officials say it remains to be seen if the longtime leader in Harare is actually willing to yield significant powers.  

U.S. diplomats had been doubtful since the Zimbabwe power-sharing talks began last September that Mr. Mugabe was serious about sharing power with his bitter political rival, and those doubts remain despite the announcement by Mr. Tsvangirai that a deal has been struck.

Mr. Tsvangirai, whose Movement for Democratic Change, the MDC, won parliamentary elections last March, is to become prime minister in a unity government while Mr. Mugabe, the country's leader since independence, will remain head of state.

The announcement came despite lingering questions about the allocation of cabinet seats between the MDC and the president's ZANU-PF party.

At a news briefing, State Department Acting Spokesman Robert Wood said doubts remain as to whether the new government will reflect the will of Zimbabweans as expressed in the 2008 elections:

"As you can understand, we are a bit skeptical. These types of things have been announced before. The key is always implementation. What's important here are actions and not words. And we want to see real serious power-sharing by the Mugabe regime. So I think the jury is still out on this one," he said.

The United States and European allies have banned weapons sales and imposed economic and travel sanctions against Mr. Mugabe, as well as his family members, and close political associates because of election and human rights abuses. The Obama administration in recent days has been reported considering a new effort in the U.N. Security Council to make the targeted sanctions global.

Spokesman Wood said the United States will in any event continue humanitarian aid to Zimbabwe to help it deal with an economic crisis and cholera outbreak it blames on misrule by Mr. Mugabe. He said it is premature to discuss lifting any sanctions because of Friday's announcement:

"We want to see what if anything comes out of this recent agreement that was reached. If and when there is a government in place in Zimbabwe that reflects the will of the Zimbabwean people, the United States will then look to see what we can do to continue to help the Zimbabwean people. But let's wait until we have a government that reflects the will of the before we go forward," he said

A senior U.S. diplomat who spoke to reporters said opposition leader Tsvangirai must feel comfortable about the arrangement he negotiated with Mr. Mugabe.

But he said the Zimbabwean leader's "track record" gives rise to serious doubts about his sincerity and it remains to be seen whether Mr. Tsvangirai is, in his words, "being played for a fool."