Senior U.S. legislators of both political parties say critical questions remain unanswered concerning America's strategy in Iraq, despite days of testimony before Congress by the top U.S. military commander in Iraq as well as the U.S. ambassador to Baghdad. From Washington, VOA's Michael Bowman reports.

Last week saw General David Petraeus and Ambassador Ryan Crocker tell members of Congress that significant military progress has been achieved in Iraq over the last year, but that the country's improved security situation is fragile and could be reversed.

Accordingly, General Petraeus said he is recommending that President Bush continue with a modest drawdown of last year's U.S. troop surge in Iraq, and then hold troop levels steady for a period of months to assess the situation.

The general's words failed to impress the Chairman of the Senate Foreign Relations Committee, Joseph Biden of Delaware, who spoke on CNN's Late Edition program.

"He [Petraeus] is saying, 'Look, we have made some progress," said Senator Biden. "We have not made a lot of progress, and what little progress we have made is reversible.' The reason it is reversible is not so much [that the U.S. is] drawing down troops, the reason is that what little political accommodation has been made [by Iraqi leaders] is very fragile. The whole deal [reason] for this surge was to provide breathing space so the parties that are killing each other - Sunni-Shi'a, Shi'a-Shi'a - stop killing one another. There is no evidence that that has been done."

Even the top Republican on the Foreign Relations Committee, Indiana Senator Richard Lugar, says the Petraus-Crocker testimony left him with doubts. Lugar also spoke on Late Edition.

"I thought the hearing demonstrated that we do not have, still, a definition of success or victory [in Iraq]," said Senator Lugar. "As a matter of fact, I asked General Petraeus for some idea of a formula for how the politics of Iraq might turn out. He really had no response to this [question]."

President Bush has said that, as security improves in Iraq, U.S. forces will be brought home so long as their absence does not put progress in Iraq at risk. He has refused to agree to a timetable for withdrawals, saying reductions in troop levels will be determined by conditions on the ground in Iraq that are impossible to predict in advance.

Appearing on CBS' Face the Nation program, Defense Secretary Robert Gates acknowledged Congress' impatience to arrive at a definitive endgame for America's involvement in Iraq. But he said the situation in Iraq remains fluid and fragile, and under such circumstances the United States must keep its future options open and flexible.

"I think people want certainty about things that no one can know," said Secretary Gates. "Very few would have thought a year ago that things would be as good as they are in Iraq despite the challenges that remain before us now."

Gates added that Iran's influence in Iraq, as well as al-Qaida's continued presence in the country, constitute additional complicating factors that must be taken into account in determining America's course of action in Iraq.