The Department of Defense fired a warning shot against the former Navy SEAL who is about to release a book with his version of the secret raid that killed Osama bin Laden.

The Pentagon addressed the letter to "Mr. Owen," the pen name of Matt Bissonnette. In the letter, Jeh Charles Johnson, from the Pentagon's office of the general counsel, says that Bissonnette signed a non-disclosure agreement that stated he would "never divulge classified information."

As we reported, the version of events described in No Easy Day, which is set for release Sept. 4, differs from the account originally put forward by Obama administration officials.

Johnson writes that Bissonnette never submitted a manuscript for their approval and the Pentagon has obtained a copy of the book and found it containes violations of the agreement.

"I write to formally advise you of your material breach and violation of your agreements, and to inform you that the Department is considering pursuing against you, and all those acting in concert with you, all remedies legally available to us in light of this situation," Johnson writes.

The Los Angeles Times reports that this is the strongest signal from the Obama administration that it is ready to crack down on leaks. If you remember, this administration has come under harsh criticism for what Republicans say is the intentional leaking of classified material for political aim.

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