Washington ? No U.S. intelligence sources or practices were compromised by the posting of secret Afghan war logs by the WikiLeaks website, the Pentagon has concluded, but the military thinks the leaks could still cause significant damage to U.S. security interests.

The assessment, outlined in a letter obtained Friday by The Associated Press, suggests that some of the Obama administration’s worst fears about the July disclosure of almost 77,000 secret U.S. war reports have so far failed to materialize.

Defense Secretary Robert Gates reported these conclusions in an Aug. 16 letter to Sen. Carl Levin, chairman of the Senate Armed Services Committee, who had requested a Pentagon assessment.

WikiLeaks, a self-described whistle-blower website, is believed to be preparing to release an even larger set of classified Pentagon documents on the Iraq war as early as Sunday.