Asked whether there was concern about the disclosure of classified information, the official said: "We are concerned about inappropriate communications. We are not going to speculate as to what is contained in these documents."
Defense Secretary Leon Panetta said in a statement given to reporters flying with him to Australia that he asked that Allen's nomination to be Commander of U.S. European Command and Supreme Allied Commander Europe be delayed "and the president has agreed."
Allen, who is now in Washington, was due to face a Senate confirmation hearing on Thursday, as was his slated successor in Afghanistan, General Joseph Dunford.
The FBI referred the case to the Pentagon on Sunday and Panetta directed the Defense Department's Inspector General to handle the investigation. Panetta informed the top Republican and Democrat on the Senate Armed Services Committee during the flight to Australia. The House Armed Services Committee was also notified.
The U.S. defense official said that Allen denied any wrongdoing and that Panetta had opted to keep him in his job while the matter was under review, and until Dunford can be confirmed to replace him - a process that gains urgency given the potentially lengthy review process and the cloud it could cast over the mission in Afghanistan.
"While the matter is under investigation and before the facts are determined, General Allen will remain commander of ISAF," Panetta said, referring to the NATOled force in Afghanistan.
The U.S. official said Panetta was informed of the matter involving Allen on Sunday, as he flew to Hawaii, after the Pentagon's top lawyer called Panetta's chief of staff. The White House was informed next.
Oh let me guess... He'll be so busy "putting his life back together" he won't testify on Thursday either. That means Hillary! will go first. Oh fun, she blew town!
So, in a nutshell, the Three Generals and One Admiral have been fired to prevent their testimony against Obama before Congress over Benghazi. Okay then. Somebody needs to man up here.