US Navy SEALs are used to bullets and bombs, but a book by one of the commandos who killed Osama bin Laden has deployed the secretive unit into the even bigger electoral battle for the White House.

"No Easy Day: The Firsthand Account Of The Mission That Killed Osama Bin Laden" is due to come out on the politically charged date of September 11, less than two months before President Barack Obama and Republican Mitt Romney face off at the polls.

Dutton, an imprint of Penguin, says the author was one of the SEALs who entered bin Laden's hideout in May 2011 "and was present at his death."

The writer is identified by the pseudonym Mark Owen and is said to have left the military after 13 consecutive combat deployments, culminating with Operation Neptune Spear in Abbottabad, Pakistan. The book is co-written with Kevin Maurer, a US journalist.

In the book, Owen says, he wants "to set the record straight about one of the most important missions in US military history. 'No Easy Day' is the story of 'the guys,' the human toll we pay, and the sacrifices we make to do this dirty job."

The cover of the book, already advertised on Amazon, shows the ghostly figure of a soldier holding a rifle, but gives little away about what's inside.

Speculation is rife over how the likely sensational story will play in a tight election where Obama is touting the al-Qaeda founder's killing in Pakistan as one of his major achievements.

As commander in chief, Obama at a minimum signed off on a mission that would have been a huge embarrassment had it ended badly. With success, Obama accomplished what his supposedly more hawkish predecessor, George W. Bush, failed to do in eight years.

However, Obama's critics -- ranging from Romney to a group of former special forces and CIA operatives -- accuse the president of leaking sensitive information to milk the mission for political gain.

Another challenge has appeared in a new book by journalist Richard Miniter, "Leading From Behind: The Reluctant President and the Advisors Who Decide for Him," which claims that Secretary of State Hillary Clinton had to prod an indecisive Obama to order the raid.

Leslie Feldman, professor of political science at Hofstra University, said the White House will be waiting anxiously for the SEAL's account.

"My gut feeling is it's not good," she told AFP. "Mitt Romney's people will be scouring every page of that book and if they come up with one little sentence they can use, one little fact, then they're going to throw that at President Obama."

"It's not good for him, but it depends on what the guy says," Feldman added.

The White House had no comment about the book on Thursday.

At the Pentagon, officials appeared to have been taken by surprise.

Books by former servicemen are meant to be checked for sensitive information and in this case, Lieutenant Colonel Jim Gregory said, "we did not receive any requests to review."

The author could face prosecution if the book reveals information that compromises national security, he added. "A decision has to be made as to the seriousness of the disclosure and the Department of Justice would be the department to follow up."

The CIA also said it had not been asked to review the text.

The politically explosive nature of the bin Laden raid was already highlighted when film producer Kathryn Bigelow agreed to push back her film "Zero Dark Thirty" to a date after the November election. The Oscar winner had come under fire from Republicans who said she was too close to the White House.

But the political loyalties of Owen remain a mystery, even if his true identity may not be secret for long.

Fox News reported that Owen is in fact Matt Bissonnette, a 36-year-old from Alaska, a revelation that one Pentagon official called "disturbing."

Fox reported that the soldier-turned-author could face legal trouble, as well as criticism from former comrades, for spilling the beans on such a secret mission.

Owen writes that his main goal is simply to help young men "become a SEAL, or at least live a life bigger than him." The publisher says that "the majority of the proceeds" from the book will be donated to charities helping the families of killed SEALs.

Don Shipley, a former SEAL who now runs a private training facility, said he's not upset by the appearance of the book.

"Whether it was right or whether it was wrong I'm sure it would have come out eventually," he told AFP in a telephone interview.

As for the debate over Obama's role, Shipley said the president needn't be worried.

"Somebody put boots on the ground in there and I think it was an incredibly ballsy move when they could have just launched a missile," he said. "The president was the one who made the decision. He can puff his chest out a little."