WASHINGTON (CNN) -- U.S. aid agencies would be overwhelmed if a major disaster struck, the U.S. Government Accountability Office warned Thursday.
"A worst-case, large-scale disaster would overwhelm voluntary organizations' current sheltering and feeding capabilities," the watchdog agency concluded in a 62-page report, citing interviews with officials of the agencies and GAO analysis.
A major earthquake in Los Angeles, California, for example, could leave 300,000 people in need of emergency shelter, but the Red Cross could provide beds for no more than 84,000 people "under optimal conditions."
The relief organizations would not have enough trained volunteers to respond to a major emergency, the investigation by the government watchdog agency found.
The official government disaster-response plan assumes that the Red Cross would play a significant role in providing care for victims, in coordination with the Federal Emergency Management Agency. But the Red Cross has been cutting staff and restructuring in response to what the GAO called "a major budget deficit."
The aid organization -- among the nation's largest -- said it is able to raise money in response to disasters but has had difficulty getting donations at other times.
A Red Cross spokeswoman acknowledged that the aid agency is having trouble raising money.
"It has been a very difficult year for fundraising with the economy, and we have also gone to Congress to seek their help," said Suzy DeFrancis, the organization's chief public affairs officer. "This has been a record year of disasters, and we need their assistance to respond to these disasters currently and be prepared for the next."
She said the aid group is being "careful not to cut our ability to deliver direct services to people."
But she said the main finding of the report is accurate.
"In a catastrophic event, no one organization can do it. The federal government can't do it alone. The Red Cross can't do it alone," DeFrancis said. "We are all going to have to work together, and I think the report showed that."
The Government Accountability Office also urged FEMA to do more to assess the capabilities of smaller aid groups.
There is a gap in communication between major aid organizations, the government and smaller aid groups, including a lack of standard terminology and measurements, the report said.
The government overhauled its emergency management systems after the terrorist attacks of September 11, 2001, and again after hurricanes Katrina and Rita in 2005.
The GAO studied the role of five major aid organizations in responding to a catastrophe: the Red Cross, the Salvation Army, the Southern Baptist Convention, Catholic Charities USA and United Way of America. Only the Red Cross is primarily a disaster-relief organization.
The Red Cross did not immediately respond to requests for comment.
FEMA said it would not comment on the report before reviewing it.
Spokeswoman Deborah Wing said only that "FEMA works every day along side the American Red Cross and other voluntary organizations to save lives and selflessly serve the American public."
FEMA criticized some aspects of the GAO's investigation as the report was being compiled. The two sides tussled in particular over the degree to which it is appropriate for a government agency to "coordinate" private-sector resources.
The GAO sent investigators to "four high-risk metro areas -- Los Angeles, Miami, New York and Washington, D.C.," and interviewed officials and examined documents from the aid organizations, government agencies and the liaisons between them.
The report, titled "Voluntary Organizations: FEMA Should More Fully Assess Organizations' Mass Care Capabilities and Update the Red Cross Role in Catastrophic Events," was compiled in response to a request from members of Congress, including the top Democrat and top Republican on the Senate Homeland Security Committee.
Aid organizations are working to help the victims of Hurricane Ike, which barrelled through Texas.
Some Ike evacuees remain in shelters, but many of them are in hotels and motels. The Federal Emergency Management Agency has a program to pay participating hotels directly for evacuees staying in them and to reimburse expenses for evacuees living in other hotels.
U.S. Department of Homeland Security Secretary Michael Chertoff said his agency and the U.S. Department of Housing and Urban Development plan to use a mixture of public housing and apartments to meet housing needs and may construct some temporary housing.
This year, the federal government declared itself "out" of the travel-trailer housing business after Hurricane Katrina, when some of the hastily constructed trailer homes were found to contain dangerous levels of formaldehyde.
Under the new National Disaster Housing Plan, it is a state's responsibility to identify housing needs and the responsibility of all levels of government to work together to fulfill those needs.