Senators on Tuesday said they would consider every avenue to fix a badly broken system of caring for troops wounded in battle, as Bush administration officials apologized anew for cases of neglect at Walter Reed Army Medical Center.

"The war in Iraq has divided our nation but the cause of supporting our troops unites us," said Sen. Carl Levin, D-Mich., who chairs the Armed Services Committee. "We will do everything we can possibly do — not as Democrats or Republicans — but as grateful Americans — to care for those who have served our nation with such honor and distinction."

As his panel questioned top defense officials, Levin also used the revelations of bad conditions and outpatient care at Walter Reed to take a swipe at President Bush's war polices.

"Today's hearing is about another example of the lack of planning for a war that was premised on the assumption that combat operations would be swift, casualties would be minimal, and that we would be welcomed as liberators, instead of being attacked by the people we liberated," he said.

Levin's panel convened the second congressional hearing in two days regarding the poor conditions at Walter Reed. Reports of wounded troops battling excessive red tape and dilapidated living conditions have enraged Republicans and Democrats, who say they are worried that problems at Walter Reed point to a broader problem of neglect across the nation at military hospitals.

Meanwhile, Bush said Tuesday he has named former Sen. Bob Dole and former Secretary of Health and Human Services Donna Shalala to lead a White House investigation.

"We have a moral obligation to provide the best possible care and treatment to the men and women who served our country," Bush said in a speech to the American Legion. "They deserve it and they're going to get it."

At Tuesday's Senate hearing, David Chu, the personnel chief at the Pentagon, also promised action.

"I'm deeply chagrined by the events that bring us to this hearing this morning," Chu said.

Sen. John McCain, R-Ariz., said Congress in coming weeks will consider whether legislation or additional resources are needed.

"I am dismayed this ever occurred," said McCain, top Republican on the Senate Armed Services Committee, who was captured and wounded during the Vietnam War. "It was a failure in the most basic tenants of command responsibility to take care of our troops."

During a hearing Monday, two soldiers wounded in combat and a spouse of a wounded soldier recounted nightmarish stories of frustration as they tried to get medical attention and disability compensation.

"I'm afraid this is just the tip of the iceberg, that, when we (get) out into the field, we may find more of this," said Rep. Tom Davis, R-Va., a member of the House Oversight and Government Reform subcommittee that held the Monday session.

Army officials said they accept responsibility but denied knowing about most of the problems.

"Simply put, I am in command," said Lt. Gen. Kevin C. Kiley, who was in charge of Walter Reed from 2000 until 2004, when he became Army surgeon general. "And as I share these failures, I also accept the responsibility and the challenge for rapid corrective action."

Kiley said he had been aware of some issues, including an October service assessment citing problems with Walter Reed staffing, medical evaluations and patient handling.

But when asked by Rep. Christopher Shays why he hadn't acted or asked Congress for money to fix the problems, Kiley said he did not think money was the issue. The general said the system for outpatient care is "complex, confusing and frustrating" and that more doctors, nurses and other staff are being brought in to lower the case load and so speed the process.

Lawmakers said they were skeptical.

"What you're saying though, under oath, is that you have all the resources necessary to you," said Shays, R-Conn. "And I honestly don't believe that. I don't believe that."

Democrats have vowed to add money to the Bush administration's request for war spending to take care of wounded active-duty troops and improve health care for retired veterans.