Appearing before the Senate Armed Services Committee, Gates expressed his desire to pull out more troops only hours after President Bush announced he was accepting the general's recommendations and ordering the drawdown to stop after July.
"The hope, depending on the conditions on the ground, is to reduce our presence further this fall," Gates said in his opening remarks. "But we must be realistic. The security situation in Iraq remains fragile and can be reversed."
While his comments may have been aimed at critics who have dismissed the pause in troop withdrawals as evidence of an "open-ended" military commitment in Iraq, Gates stopped short of offering a firm commitment to removing additional forces later this year.
Indeed, the secretary said he no longer believes that troop levels in Iraq could drop below 100,000 by January, as he had hoped late last year. He also emphasized that any further troop pullouts this year would reflect military commanders' operational needs.
Gates' testimony capped this week's high-profile hearings on the war, during which Petraeus called for a 45-day period of "consolidation and evaluation" in late July, when the force level is expected to be about 140,000 troops. This waiting period would be followed by an indefinite assessment period to determine if the military can pull more troops out without jeopardizing the security gains in Iraq.
At the White House Thursday, Bush publicly endorsed the commander's approach, saying he will give Petraeus "all the time he needs" -- a statement that brought swift attacks from key Democrats on Capitol Hill.
"Instead of continuous reductions beyond pre-surge levels or even a brief pause, what President Bush did this morning is reinforced our open-ended commitment in Iraq by suspending troop reductions in July for an unlimited period of time," said Senate Armed Services Committee Chairman Carl Levin, D-Mich.
Responding to the congressional criticisms, Gates urged Levin and other lawmakers not to dismiss the advice of military leaders, who have all endorsed the strategy, so quickly.
"Some have lamented what they believe was an unwillingness to listen to our military professionals at the beginning of this war," Gates said. "I hope that people will now not dismiss as irrelevant the unanimous views of the field commander, CENTCOM [Central Command] commander and joint chiefs."
Also Thursday, Levin criticized the Pentagon for its plans to shift roughly $600 million away from Iraqi Security Forces training and equipment programs into accounts for construction and infrastructure improvements.
Levin has led a growing chorus of lawmakers who want the Iraqi government to take on more of the financial responsibility for the country's reconstruction.
In a letter sent to Gates shortly before the hearing, Levin said that the money transfer ran counter to testimony from Ryan Crocker, U.S. ambassador to Iraq, who told the committee April 8 that the "era of U.S.-funded major infrastructure projects is over."
Gates said he was unaware of the transfer of funds and said he would look into the matter.