The Pentagon said Tuesday that "No Easy Day," a controversial new book written by a former Navy SEAL who participated in the raid that killed Osama bin Laden, reveals classified information, The Associated Press reported. Rear Adm. Sean Pybus, who heads the Naval Special Warfare Command, said details in the book might put forces and their families in harm's way. In a letter sent to about 8,000 people in NSWC, including more than 2,000 SEALS, on the day the book was officially released, Pybus warned his forces to stop releasing details about their secretive world. The letter, obtained by The Associated Press, also said that too many members of the community have violated their ethos to not publicize the nature of their work and not to seek recognition for it. "For an elite force that should be humble and disciplined for life, we are certainly not appearing to be so," Pybus wrote. "We owe our chain of command much better than this." The Pentagon said it is still reviewing what legal options should be taken against the author.