WASHINGTON – Khalid Sheikh Mohammed’s claims that he was responsible for dozens of successful, foiled and imagined attacks in the past 15 years relies on a loose definition of the word “responsible.” Officials say the 9/11 mastermind was key to some plots but a bit player in others.

The 31 on his list range from the stunningly vicious suicide hijackings of Sept. 11, 2001, to others that current and former government officials say were more talk than concrete plans, such as a plot to kill Jimmy Carter and other former U.S. presidents.

The officials spoke on condition of anonymity, noting Mohammed’s activities are likely to be the subject of an upcoming military tribunal.

His confession came in a closed-door hearing in the newly established U.S. tribunal process. A 26-page transcript of the Saturday session at Guantanamo Bay, Cuba, was made public Wednesday night.

While there apparently is truth in much of the statement, several officials said, there’s also an element of self-promotion. They view the claims as at least in part a rallying cry to bolster his image and that of al-Qaida in the only venue Mohammed has left: a military courtroom from which the public is barred.

“I have never known a criminal – either terrorist or otherwise – that didn’t exaggerate,” said Michigan Rep. Mike Rogers, a former FBI agent and the top Republican on the terrorism panel of the House Intelligence Committee.

Pentagon spokesman Bryan Whitman said authorities would decide the credibility of Mohammed’s claims if he is tried. “These are his words,” Whitman said.

The U.S. linked Mohammed closely to the attacks of 9/11, and his statement said he was responsible “from A to Z.”

Officials don’t doubt his claim that he beheaded Wall Street Journal reporter Daniel Pearl with what he called his “blessed right hand.” And he corroborates al-Qaida’s known interest in attacking embassies, London’s Heathrow Airport, the New York Stock Exchange and other targets.

But his role in some plots may be more minor than his hands-on involvement in coordinating the attacks of 9/11 – evidence of which was found on his computer when he was captured. Some of the plots were formulated in al-Qaida’s early years, when alliances among jihadists were even more fluid than they are today.

“If you look at him having a senior position in al-Qaida, when he says he’s responsible, it can be interpreted in a lot of different ways,” said Ben Venzke, head of the Virginia-based IntelCenter, a government contractor that monitors al-Qaida messaging.

Associated Press writers Victor L. Simpson in Rome and Pauline Jelinek in Washington contributed to this story.