WASHINGTON (CNN) -- The White House promised an "exhaustive look" at conditions at the Army's premier hospital Monday after the service's top civilian official resigned last week.

"The president and also everybody within the chain of command are taking responsibility," White House spokesman Tony Snow said. "It's time to shine a bright light on the entire system and find out where the failings may be and address them."

Wounded veterans of the war in Iraq appeared before a House subcommittee Monday to tell stories of being housed at a moldy, shopworn outpatient facility at Washington's Walter Reed Army Medical Center, and detail how they struggled to obtain follow-up care after their initial treatment. Washington Post reporting led to an outcry that brought the Thursday sacking of the facility's commander, Maj. Gen. George Weightman, and Friday's resignation of Army Secretary Francis Harvey.

The House Oversight and Government Reform committee released documents last week showing Weightman was warned in September that the Army's decision to turn over support services for the facility to a private contractor sparked an exodus of skilled staff. That left patient care "at risk of mission failure," the hospital's garrison commander, Col. Peter Garibaldi, warned in a memo to the general.

Snow said the Bush administration has taken "very swift and definitive action" by shaking up the service's leadership and assigning a medical review team to assess conditions at Walter Reed and the Navy's flagship hospital at nearby Bethesda, Md. In addition, President Bush announced last week that he would name a bipartisan commission to assess medical care for wounded U.S. troops.

"We'll take a very exhaustive look at this," Snow said. "It is very important to figure out what's wrong and get it fixed, and the president is committed to that."