The National Archives has told the nation’s intelligence agencies to stop pulling once-declassified historical records from public access and to return many of the documents they have removed, The New York Times reported today. Allen Weinstein, the archivist of the United States, called for a “moratorium” on the reclassification of records until an investigation determines which should be secret.

The Times reported last month that historians had discovered that old documents that they had once studied freely had been removed from public files, even though they seemed to contain nothing of importance to national security. The scholars learned that, since 1999, a secret intelligence program had pulled more than 55,000 pages of documents that officials felt should not have been declassified.