Adelaide, Australia ? David Hicks, an Australian who is the only person convicted on terrorism charges at a U.S. military tribunal at Guantanamo Bay, walked free today after more than six years behind bars.

The 32-year-old was released from prison in his hometown of Adelaide in southern Australia after completing a nine-month sentence struck under a plea deal that followed more than five years’ detention without a trial at Guantanamo.

Hicks smiled briefly as he was led by guards toward the gate of the Yatala Labor Prison, but did not speak to reporters.

In a statement released by his attorney he thanked supporters, including rights activists and anti-torture groups who helped get him out of Guantanamo Bay, and said he did not want to do “anything that might result in my return there.”

“First and foremost I would like to recognize the huge debt of gratitude that I owe the Australian public for getting me home,” Hicks said in the statement. “I will not forget, or let you down.”

Last week, a federal magistrate ruled that Hicks was a security risk because of the training he acknowledged receiving in terrorist camps in Afghanistan. The court was told he met al-Qaida leader Osama bin Laden at least 20 times, describing him as a “lovely brother” in letters home.

The magistrate ordered Hicks to report to police three times a week and obey a curfew by staying indoors at premises to be agreed on by police.

The former Muslim convert – he has renounced the faith while in detention – was caught on the side of the Taliban in Afghanistan in December 2001 by U.S.-backed local forces and handed to American authorities.

During his incarceration at Guantanamo, Hicks became a cause celebre in Australia, where many activists and politicians criticized former Prime Minister John Howard for allowing an Australian to languish for years in a foreign jail without trial.

Under increasing pressure as a tough election battle approached, Howard raised the issue of Hicks with U.S. Vice President Dick Cheney during a visit to Sydney earlier this year, and the tribunal proceedings against Hicks started soon afterward.

Hicks became the first person convicted under the military tribunals system set up by President Bush to try terror suspects, when he pleaded guilty in March to providing material support to a terrorist organization.

He was sentenced to seven years in prison, though all but nine months’ prison time was suspended. Under the plea deal, Hicks was returned to Australia to serve out his time, agreed to remain silent about his treatment in custody and forfeited any right to appeal his conviction.

He also agreed not to speak with media until March next year.

After earlier suggesting Hicks would apologize for his past actions, his father, Terry, said today his son believed there was no need.

“You’ve got to realize David’s done five and a half years pretty tough,” Terry Hicks told reporters. “I think he’s done his time for whatever. Nothing’s been proved of what he’s supposedly done. He’s done his time and it’s time for him to settle down.”