The top U.S. commander for the Mideast said Wednesday he is optimistic U.S. forces can stabilize Iraq, but warned against a timetable for a phased withdrawal.

The remarks seem to put Army Gen. John Abizaid, head of U.S. Central Command, in the direct line of fire from a newly-empowered Democratic leadership, which launched its first salvo when Sen. Carl Levin said he thinks U.S. troops need to start pulling out of Iraq.

"We cannot save the Iraqis from themselves. The only way for Iraqi leaders to squarely face that reality is for President Bush to tell them that the United States will begin a phased redeployment of our forces within four to six months," said Levin, D-Mich., who is set to become chairman of the Armed Services Committee where Abizaid was testifying.

Abizaid along with the State Department's senior adviser on Iraq David Satterfield, CIA Director Gen. Michael Hayden and Defense Intelligence Agency Director Lt. Gen. Michael Maples were testifying before Levin and other Senate Armed Services Committee members. Abizaid and Satterfield were set to repeat their performances before the House Armed Services panel later in the day.

These are the first hearings on Iraq since Democrats won majority control of the House and Senate and Defense Secretary Donald Rumsfeld resigned. Republicans will keep control of committee leadership positions during the lame duck session. The 110th Congress convenes in January.

Abizaid acknowledged that while not much has changed since he last testified to the panel in August, he repeated that "failure to stabilize Iraq could increase Iranian aggressiveness and embolden Al Qaeda's ideology."

"I remain optimistic that we can stabilize Iraq," he said. "The changing security challenges in Iraq require changes to our own approach to achieve stability. Let me remind the committee, however, that, while new options are explored and debated, my testimony should not be taken to imply approval of shifts in direction."

The hearings offer the first indication of what positions lawmakers will take on Iraq when leadership control changes.

"Iraq has to be done on a bipartisan basis," said Sen. Harry Reid, elected on Tuesday to be the next Senate majority leader. "We know how the American people feel. They want a change of course in Iraq."

On top of his desire to see a phased withdrawal of troops, Reid, D-Nev., is planning to seek an additional $75 billion for the military to repair damaged combat units, said spokesman Jim Manley.

Manley said the $75 billion that Reid wants would be on top of the $70 billion Congress recently appropriated for 2007 operations in Iraq and Afghanistan.

Bill Nelson, D-Fla., a member of the committee, told FOX News Abizaid "is the only one that told it like it was" when he testified previously. But he said while it's necessary to listen to "the professional commanders on the ground" before deciding on a political, negotiated solution, he also wants to hear from the bipartisan Iraq Study Group led by Republican James A. Baker III and Democrat Lee Hamilton, British Prime Minister Tony Blair and defense secretary nominee Bob Gates.

"You need to listen to a composite of all of this in order to determine what's in the interest of the United States at the end of the day, which is, if we can, before the chaos, have a stabilized Iraq," Nelson said.

Abizaid said the U.S. force level of 141,000 troops is fine for now, though it may have to increase for temporary efforts associated with training Iraqi forces. But when pressed by Sen. Jack Reed, D-R.I., on how much time the U.S. and Iraqi force have to reduce the violence in Baghdad before it spirals beyond control, Abizaid offered a calendar similar to Levin's.

"I think it needs to be brought down in the next several months, four to six months," he said.

Abizaid also acknowledged that it would have been advisable to have more troops in June and July when the Iraqi government was trying to increase its security efforts in Baghdad and Al-Anbar province, where the Sunni stronghold of Fallujah is located.

Abizaid, who made a surprise visit to Iraq earlier this week, said he was confident after meeting with Gen. George Casey, head of the Multinational Force in Iraq, and Iraqi military leaders that the Iraqi military forces were becoming more professional and better able to target Shiite death squads. Abizaid noted that 80 percent of the violence takes place within 35 miles of Baghdad.

"Iraqis and Americans alike believe that Iraq can stabilize and that the key to stabilization is effective, loyal, nonsectarian Iraqi security forces, coupled with an effective government of national unity," he said.

"In discussions with our commanders and Iraqi leaders, it is clear that they believe Iraqis forces can take more control faster, provided we invest more manpower and resources into the coalition military transition teams, speed the delivery of logistics and mobility enablers and embrace an aggressive Iraqi-led effort to disarm illegal militias," the general added.

On the diplomatic front, Satterfield said the United States is "prepared in principle for dialogue with Iran," but the timing is uncertain. Iran is blamed for helping incite and arm much of the internecine fighting in its neighbor's territory.

Satterfield also said that getting control of the militias is key and suggested an "amnesty plan that comprehensively gives militants incentives to return to civilian life."

"Iraqis must establish a robust process aimed at disarming, demobilizing and reintegrating members of armed groups into normal Iraqi society," Satterfield said. He said the State Department will duly consider the ISG recommendations.

Members of the Senate committee include Sens. Hillary Clinton, D-N.Y., and John McCain, R-Ariz., both potential presidential contenders. Republican Rep. Duncan Hunter of California, chairman of the House panel, also has expressed presidential ambitions. The hearings provided each opportunity to offer their perspectives on Iraq.

McCain used his chance to press Abizaid about whether the multinational command had enough troops, considering that Iraqi police uniformed-clad men were able to kidnap members of the Interior Ministry on Tuesday.

"General, I think you're advocating the status quo here today," McCain said, adding that it was "made clear in the last election that is not an acceptable position for the American people. ... I respect you enormously, I appreciate your service, I regret deeply that you seem to think that the status quo and the rate of progress we're making is acceptable. I think most Americans do not."

"Senator, I agree with you. The status quo is not acceptable, and I don't believe what I am saying here today is the status quo," Abizaid responded. "What I am saying is that we must significantly increase our ability to help the Iraqi army by putting more American troops with Iraqi units in military transition teams to speed the amount of training that is done, to speed the amount of heavy weapons that gets there."

While Democrats have been arguing for months that Iraq is in a rut, some Republicans have only recently added their concerns to the mix, saying the country is leaning toward civil war and needs change. Sen. John Warner, R-Va, chairman of the Armed Services Committee, said in October that the war was "drifting sideways."

Repeating that language on Wednesday, Warner, who opposes setting a date to begin pulling troops out of Iraq, said he won't suggest a major change in course right away. He said he wants first to see recommendations from the ISG as well as an internal assessment under way at the Pentagon.

Baker and Hamilton are expected to unveil their report next month.

"I urge my colleagues ... to carefully study all of the material as we develop in this committee and elsewhere and then reach individual and collective recommendations for the Senate and indeed for the president on the future strategy in Iraq," Warner said at the hearing.

Sen. Christopher Dodd, a member of the Foreign Relations Committee, said he doesn't expect the ISG to recommend a specific timetable.

"I think they'll probably be deferring a lot to commanders on the ground on how to do that," said Dodd, D-Conn. "I think they may talk about timeframes but leaving the details to the people on the ground who have to make those decisions."

FOX News’ Molly Henneberg and The Associated Press contributed to this report.