WASHINGTON (AP) -- The Veterans Affairs' vast network of 1,400 health clinics and hospitals is beset by maintenance problems such as mold, leaking roofs and even a colony of bats, an internal review says.

The investigation, ordered two weeks ago by VA Secretary Jim Nicholson, is the first topdown review of the facilities conducted since the disclosure of squalid conditions at Walter Reed Army Medical Center.

A copy of the report was provided to The Associated Press.

The report found that 90 percent of the 1,100 problems cited were deemed to be of a more routine nature: worn-out carpet, peeling paint, mice sightings and dead bugs at VA centers.

The other 10 percent were considered serious and included mold spreading in patient care areas. Eight cases were so troubling they required immediate attention and follow-up action, according to the 94-page review.

Some of the more striking problems were found at a VA clinic in White City, Ore. There, officials reported roof leaks throughout the facility, requiring them to ''continuously repair the leaks upon occurrence, clean up any mold presence if any exists, spray or remove ceiling tiles.''

In addition, large colonies of Mexican Wing-tailed bats resided outside the facility and sometimes flew into the attics and interior parts of the building.

''Eradication has been discussed but the uniqueness of the situation (the number of colonies) makes it challenging to accomplish,'' according to the report, which said the bats were being tested for diseases. ''Also, the bats keep the insect pollution to a minimum which is beneficial.''

In other findings:

--In Oklahoma City, secondhand smoke from an outside smoking shelter sometimes infiltrated the building through the women's restroom.

--Deteriorating walls and hallways were common, requiring repair, patch and paint in 30 percent of patient areas in Little Rock, Ark.

--Numerous unspecified ''environmental conditions'' affected the quality of the building in New York's Hudson Valley, with the private landlord repeatedly refusing to fix problems. The VA is taking steps to relocate to another facility.

--Roof leaks or mold at facilities such as Hudson Valley; North Chicago, Ill.; Indianapolis; Puget Sound, Wash.; Portland, Ore; and Fayetteville, Ark.

In response, Nicholson this week ordered ''immediate corrective action'' to fix problems, with full accounting provided to the VA. He noted that an overwhelming majority of the issues were normal ''wear and tear'' items.

In many cases where there were roof leaks or mold, officials had begun action to order patches or repairs, the department said. In some instances, they were moving to new facilities.

''The level of detail in the reports and the corrective actions enumerated demonstrate your responsiveness to my request,'' Nicholson wrote in an order Monday to VA medical center directors.

In interviews, VA officials said they were somewhat reassured by the report, which they said indicated no red flags rising to the level of problems at outpatient facilities at Walter Reed in Washington, D.C., one of the premier facilities for treating those wounded in Iraq and Afghanistan.

Walter Reed is a military hospital run by the Defense Department. Critics long have said problems of military care extend to the VA's vast network, which provides supplemental health care and rehabilitation to 5.8 million veterans.

''There was no imminent threat of harm to patients,'' said Louise Van Diepen, chief of staff to VA's acting undersecretary for health, Michael Kussman. ''We have no indication to lead us to believe there is a smoking gun.''

''Could it happen? Yes. But we're doing everything we can prospectively to monitor the situation,'' she said.

Three high-level Pentagon officials have been forced to step down after the disclosures last month at Walter Reed. The controversy also has led to investigations by congressional committees, a presidential task force and the Pentagon.

A separate review of the VA system for handling disability claims is under way to determine how to cut through bureaucratic delays, confusing paperwork and long appeals process as thousands of veterans return home from Iraq and Afghanistan.

Investigators this month determined that the system was strained to its limit, with backlogs of more than 400,000 and delays and appeals that could take years.