- Video report by ITV News Security Editor Rohit Kachroo
A convicted al-Qaida "sleeper agent" linked to the architects of the 9/11 terrorist attacks has claimed he was tortured while being held as an enemy combatant on American soil.
Speaking for the first time, Ali al-Marri, a Qatari man who served 13 years in US jails, said he wants his interrogators to be brought to account, accusing them of restraining him using duct tape and subjecting him to what he described as 'dry-boarding'.
"I have never experienced death, but I assume this is the nearest thing to dying," he told ITV News.
"You’re suffocating, you can see your life coming out of your face and you cannot even move."
Al-Marri was one of the most high-profile detainees on the American mainland during the early years of the so-called 'War on Terror', and was accused of being in direct contact with Khalid Sheikh Mohammed, the mastermind behind the 9/11 attacks.
The Qatari national had travelled to the United States with his wife and five children legally on 10 September 2001, the day before the attacks, to attend graduate school in Illinois.
He was initially charged with fraud based on information found on his computer, but the then-president, George Bush, later declared him an enemy combatant.
But although al-Marri could have faced up to 15 years in prison, US district judge Michael Mihm handed down a lighter sentence of eight years and four months in consideration of what he called "very severe" conditions at the US naval brig in South Carolina where he had been detained.
Al-Marri alleges that threats were made to his wife and children while being held in solitary confinement.
Although it is impossible to independently verify his claims, the judge described his treatment in detention as "unacceptable".
He claims an FBI interrogator stuffed his mouth with socks and wrapped his face with duct tape to stop him chanting.
"I started reciting the Quran… They put socks in my mouth… I was uncooperative… So (an interrogator) put pressure on my jaw on an area where if he presses too hard I had to open my mouth…
"I am choking, and I cannot move. My hands, my feet. The first thing you do is take it off, but I can't. The chain is tied, and I can't do that. The feeling of not being able to save myself… was hard... To be helpless. I start choking."
US government documents seen by ITV News describe the interrogation that day and corroborate aspects of al-Marri's account.
The briefing note says: "On 11 March 2004, in response to al-Marri's continuous chanting in Arabic, the lead interrogator wrapped duct tape over al-Marri's mouth on three occasions".
The summary adds that al-Marri "had no difficulty breathing and did not appear to gag, except for a brief moment at the end".
In a statement released to ITV News, the FBI said it would not comment on al-Marri's specific allegations but said it "does not engage in torture and we maintain that rapport-building techniques are the most effective means of obtaining accurate information in an interrogation".
Al-Marri is now being supported by a solicitor in the United States and the British advocacy group Cage to help him "adjust and process the trauma that he endured".
Asked why he had chosen now to make the allegations, three years after his release, a spokesman said he had been busy "resettling into normality and connecting with his family".
Despite admitting terrorism charges, al-Marri claims the accusations were "100 percent false".
He says he rejected legal advice during his trial and agreed to a plea bargain to serve a shorter prison sentence.
"Every single accusation of terrorism in the plea bargain is false, but I was not given a choice," he said, adding: "I was never, ever a member of al-Qaida or any jihadist organisation".