WASHINGTON – The Pentagon formally warned a former Navy SEAL who has written a first-person account of the raid that killed Osama bin Laden last year, saying he has violated his signed agreement not to divulge classified information, and it threatened him with stiff legal action.

“In the judgment of the Department of Defense, you are in material breach and violation of the non-disclosure agreements you signed,” Pentagon General Counsel Jeh Johnson said Thursday in a letter addressed to Mark Owen, the pen name of Matt Bissonnette.

Johnson did not specify what in Bissonnette’s forthcoming book, “No Easy Day,” constitutes improperly disclosed classified information. But he said military lawyers are considering “all legal remedies available to us.”