The government improperly sealed hundreds of previously public CIA, Pentagon and other records by reclassifying them as secret on questionable grounds, an internal review said Wednesday.

The National Archives' audit of thousands of records withdrawn from public view since 1995 contends that one of every three was resealed without justification.

The investigation covered historical records held by the National Archives. But it comes amid broader debate on classifying records on national security grounds, which critics say is often done based on political expediency.

The Associated Press reported earlier this month that the National Archives agreed to seal previously public records _ many of them more than 50 years old _ despite concerns about whether it was justified.

On the other hand, Democrats have decried the timing of President Bush's 2003 decision to declassify sensitive intelligence and authorize its disclosure to rebut Iraq war critics. In recent weeks, the CIA has fired an employee accused of sharing classified information with news media.

"The ability and authority to classify national security information is a critical tool at the disposal of the government and its leaders," said William Leonard, head of the Archives' information security oversight office, in a briefing with reporters.

Such a system, Leonard said, is only effective if the 3 million federal workers who decide whether to seal records on national security grounds each day follow clear standards and are kept honest.

While the audit found numerous instances of improper reclassification, the National Archives declined to release details of what those documents contained, saying it was still working with the agencies to make them public again.

According to the audit:

_At least 32,315 publicly available records were reclassified since 1995, primarily by the U.S. Air Force (17,702), CIA (3,147) and Energy Department (2,164). Based on a sampling of 1,353 of those documents, 24 percent were resealed on clearly inappropriate grounds, while another 12 percent were questionable.

_Poor oversight by the agencies and the National Archives was to blame, primarily due to a lack of clear standards and protocol for reclassification.

_In many cases where a previously public document was resealed on national security grounds, the decision didn't make sense because the material had been published elsewhere.

National Archivist Allen Weinstein said at the news briefing that he was implementing new procedures to curtail abuses and ensure that resealing of documents is rare. The procedures require that the public be informed on a regular basis when records are withdrawn from public access.

The archives also will boost training, seek more federal funding to speed declassification and launch a longer-term study of how it handles materials that are deemed classified.

The archives' secret agreements with government agencies were made public earlier this month in response to a 3-year-old Freedom of Information Act request by The Associated Press. They provided new details on the efforts of the nation's chief historical repository to hide the fact that U.S. intelligence was secretly trying to reclassify approximately 55,500 pages of previously public documents.

The revelation drew widespread anger on Capitol Hill, and the agreement was even disowned by a former head of the archives. John Carlin, a former Kansas governor who served as chief archivist from 1995 to 2004, said the agreement was kept secret even from him.

"I was shocked by the content, particularly the language that it was in the best interest of the National Archives to keep the public in the dark," he said in a statement last week. "I spent most of my tenure stating that NARA is a public trust _ this (agreement) undermines that trust."

Archives officials have been criticized for keeping the agreements secret. But internal NARA reports obtained by the AP under the Freedom of Information Act show archivists were concerned about the reclassification scheme as early as January 2003. As boxes of documents were pulled from shelves, historians and other researchers who regularly use archival materials were beginning to notice their absence.

"Researchers continue to question why records, some of which have been open for years, are not readily available for research in 2003," archivists said in a January 2003 report. "The exceptional efforts of the (staff) ... have worked to placate most of the impacted researchers, and complaints are amazingly few in number."

Two years later, NARA officials appeared frustrated by the reclassification effort.

"The amount of disruption to timely reference service wreaked by ... declassification (sic!) teams is growing," a NARA official said in an April 2005 report. "The Air Force team seems particularly bent on expanding their mandate to series of records well beyond recognized rationality considering the sort of information they are allegedly seeking to identify."