The U.S. 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 in Washington, the U.S. Army's flagship hospital.

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 in the Pacific northwest state of Oregon. 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 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.

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.