WASHINGTON  -- The Inspector general of US Defense Department has cleared US commander in Afghanistan John Allen of misconduct following an investigation into whether he exchanged inappropriate e-mails with Tampa socialite Jill Kelley, US media reported.

In a letter sent to Allen Friday, the inspector general wrote that Allen had not violated military prohibitions against conduct unbecoming of an officer, the Washington Post reported. It quoted a senior US official as saying Allen "was completely exonerated. "

Allen was suspected of having inappropriate correspondence with Kelley, who was involved in a scandal that prompted the resignation of former Central Intelligence Agency Director David Petraeus.

During an investigation of Petraeus, the FBI uncovered messages between Allen and Kelley, who served as a liaison between the civilian society and U.S. Central Command in Tampa, Florida, which was then led by Allen during the time of the exchange. Defense Secretary Leon Panetta ordered a formal inquiry.

The investigation prompted the White House to place on hold Allen's nomination to become the supreme allied commander in Europe. Allen is scheduled to relinquish command in Afghanistan early next month, and the Pentagon has not yet requested that the Senate Armed Services Committee reschedule his nomination hearing.