Pentagon threatens to sue former US Navy Seal for publishing book on killing of Osama Bin Laden

The book claims Bin Laden was not armed when he was shot (AP)

Saying that it will pursue "all remedies legally available to us," the Pentagon is threatening to sue the former US Navy Seal who is about to publish a memoir detailing his role in the killing of Osama Bin Laden.

A letter to Matt Bissonnette, a member of the team which raided the terrorist's hideout in Pakistan last year, argues that Tuesday's scheduled launch of his book No Easy Day would represent a "material breach" of legally binding non-disclosure agreements.

"Public dissemination of your book will aggravate your breach and violation of your agreements," it warned, citing contracts he signed in 2007. "You have a continuing obligation to 'never divulge' classified information."

Mr Bissonnette, who used the pseudonym Mark Owen, told how he was part of a team who discovered Bin Laden cowering in a bedroom on the upper floor of his hideaway, next to two women who were "hysterically crying and wailing in Arabic".

The terrorist, who wore a sleeveless T-shirt, loose beige trousers and a brown tunic, was twitching and convulsing after having been shot by the first "point" man into the room. Mr Bissonnette fired several more rounds into his body.

His team then formally identified the dead man as Bin Laden. Two empty firearms were found during a search of the area, leading them to conclude that he "hadn't even prepared a defence" and had "no intention of fighting."

Though undeniably dramatic, the account is also highly controversial, because it sheds light on a still-classified raid. In statements released by Dutton, his publisher, Bissonnette has argued that it "adheres to my strict desire not to disclose confidential or sensitive information" and claims that a portion of profits from the book will be donated to charities that benefit families of fallen Seals.

No fewer than 575,000 hardback copies of No Easy Day have already rolled off the presses, some of which have been leaked. And the book is already number one on Amazon's charts, thanks to pre-sales.

Mr Bissonnette, who was identified last week by US news outlets, has striven to keep his identity secret. Prior to filming an interview with the US television show 60 Minutes, which is due to be aired next week, he used a team of make-up artists to alter his appearance.

Conspiracy theorists are meanwhile wondering if the Pentagon's efforts to suppress the book are politically motivated, since one excerpt from the book claims that "none of [the Seal team] were huge fans of Obama."

No Easy Day

More than half a million hardback copies of the book have rolled off the presses already