WASHINGTON — The Bush administration's Iraq policy has left the United States with insufficient resources to protect itself from attack, the top Democrat on the House Armed Services Committee said Wednesday.

"When looking at the needs in Afghanistan, the effort in Iraq — however important — is putting at risk our ability to decisively defeat those most likely to attack us," said Rep. Ike Skelton, D-Mo. "Iraq is also preventing us from effectively preparing for the next conflict."

Skelton's comments came on the second day of testimony by Gen. David Petraeus, the top U.S. commander in Iraq, and Ryan Crocker, the U.S. ambassador there. Petraeus told lawmakers that security gains in the war zone are too fragile to promise further drawdowns.

"The situation in certain areas is still unsatisfactory and innumerable challenges remain," Petraeus told the House panel.

Crocker said political and economic process in recent months has been significant, but added: "I must underscore, however, that these gains are fragile, and they are reversible."

Republicans were considerably more optimistic about the situation in Iraq than last year.

"No one can deny that the security situation in Iraq has improved," said Rep. Duncan Hunter of California, the No. 1 Republican on the committee.

Petraeus said he has recommended to President Bush that the U.S. complete, by the end of July, the withdrawal of the 20,000 extra troops. Beyond that, the general proposed a 45-day period of "consolidation and evaluation," to be followed by an indefinite period of assessment before he would recommend any further pullouts.

The White House signaled Wednesday — as Bush has for weeks — that it was likely the president would embrace recommendations of Petraeus and his generals in the field. White House press secretary Dana Perino said it is "within the realm of possibility" that Bush would discuss in his Thursday speech the length of soldiers' tours of duty in Iraq. The administration is expected to announce this week that tours would be reduced from the current 15 months to 12 months.

Perino would not discuss specifics of Bush's remarks, citing the ongoing testimony on Capitol Hill by the United States' top figures in Iraq and a White House meeting Wednesday afternoon between the president and congressional leaders of both parties. But she left no doubt that the shape of the decision is all but done, and essentially ruled out that anything lawmakers say could change his mind.

"I think the president has gotten a lot of advice," she said. "I think he's pretty far down the path of what he's going to say tomorrow."

Democrats say pausing troop reductions would signal to the Iraqis that the United States was committed to the war indefinitely. They plan to push legislation this spring that would force the Iraqi government to spend its own surplus in oil revenues to rebuild the country, sparing U.S. dollars.

"This nation is facing record deficits and the Iraqis have translated their oil revenues into budget surpluses rather than effective services," Skelton said. "Under these circumstances and with the strategic risk to our nation and our military readiness, we and the American people must ask — why should we stay in Iraq in large numbers?"

Iraq is looking at a potential boon in oil revenue this year, possibly as much as $100 billion in 2007 and 2008. Meanwhile, the U.S. military is having to buy its fuel on the open market, paying on average $3.23 a gallon and spending some $153 million a month in Iraq on fuel alone.

While Iraq pays for fuel for its own troops, it has relied heavily on U.S. dollars to provide people with basic services, including more than $45 billion for reconstruction.

Sen. Carl Levin, chairman of the Senate Armed Services Committee, estimated on Tuesday that Iraq has some $30 billion in U.S. banks. He said he expects legislation addressing the issue will be proposed as part of this year's war spending bill or the 2009 defense authorization bill.

Lacking the votes to order troops home by a certain date, Democrats see fencing off reconstruction money as an alternative to challenging the Bush administration's Iraq policies. And several Republicans have signaled their concerns about burgeoning Iraqi oil revenues at a time when the war is growing increasingly costly.