WASHINGTON — Flayed by lawmakers' criticism, Army leaders said Monday they accept responsibility for substandard conditions at the service's flagship Walter Reed Army Medical Center but also said they hadn't known about most of the problems.

Democrats and Republicans alike suggested the failings go far beyond the one hospital for wounded soldiers in Washington, and they demanded action. Military leaders — and Vice President Dick Cheney — promised they'd get it.

"We can't fail one of these soldiers or their families, not one. And we did," said Maj. Gen. George W. Weightman, who was in charge of Walter Reed from August 2006 until he was fired last week. He added, "We did not fully recognize the frustrating bureaucratic and administrative processes some of these soldiers go through. We should have, and in this I failed."

Weightman's comments were echoed by other top Army officials at an emotional House hearing held at the hospital itself as Congress began digging into the controversy.

In a session that mixed contrition and clashes, lawmakers said dilapidated housing and excessive red tape were problems beyond Walter Reed, underscoring how recent revelations about the hospital have become a metaphor for broader concerns about the government's treatment of soldiers returning from wars in Iraq and Afghanistan.

"I'm afraid this is just the tip of the iceberg, that when we got 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 session.

"Building 18 is just one visible symptom of a far more insidious and pervasive malady. All the plaster and paint in the world won't cure a system that seems institutionally predisposed to treat wounded soldiers like inconveniences rather than heroes," Davis said.

"My question is, where have you been?" Rep. John Tierney, D-Mass., chairman of the panel, asked Army Undersecretary Peter Geren, Army Chief of Staff Gen. Peter Schoomaker and Vice Chief Gen. Richard Cody.

In one exchange, Schoomaker told Tierney, "I've got a daughter and a son-in-law that are on the way to combat. This is not something about people who don't care. And I am not going to sit here and have anybody tell me that we don't care about —"

"Nobody said anything about people not caring, so we'll put that red herring aside and, if I can, calm you down and get you back to the issue here," Tierney answered.

Lawmakers listened as several patients testified with stories of lax or poor treatment at Walter Reed.

Staff Sgt. John Daniel Shannon, who lost his left eye and suffered traumatic brain injuries from a rifle wound, said that after he was discharged from Walter Reed, he was given a map of the grounds and eventually found his way to outpatient quarters by wandering around and asking for directions.