An internal Pentagon review this year found systemic problems ... in the military's efforts to obtain records from American banks and consumer credit agencies in terrorism and espionage investigations, according to Pentagon documents. The newly disclosed documents, totaling more than 1,000 pages, provide additional confirmation of the military's expanding use of what are known as national security letters under powers claimed under the Patriot Act. The documents show that the military has issued at least 270 of the letters since 2005, and about 500 in all since 2001. The documents were obtained through the Freedom of Information Act by two private advocacy groups, the American Civil Liberties Union and the Electronic Frontier Foundation. The New York Times first disclosed the military's use of the letters in January, and senior members of Congress and civil liberties groups criticized the practice on grounds that it seemed to conflict with traditional Pentagon rules against domestic law enforcement operations. The documents raise a number of apparent discrepancies between the Defense Department's internal practices and what officials have said publicly and to Congress about their use of the letters. The documents suggest, for instance, that military officials used the F.B.I. to collect records for what started as purely military investigations. And the documents also leave open the possibility that records could be gathered on nonmilitary personnel in the course of the investigations. Civil liberties advocates said recent controversy over the Department of Defense's collection of information on antiwar protesters made them suspicious of the assertion that the letters had been used exclusively to focus on military personnel. "We are very skeptical that the D.O.D. is voluntarily limiting its own surveillance power," said Melissa Goodman, a staff attorney for the A.C.L.U..

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