The unexpected guilty plea of an Australian who was the first Guantanamo detainee to stand trial before a military tribunal was likely linked to a deal with prosecutors, the man's father said Tuesday.

David Hicks, a 31-year-old former kangaroo skinner, entered the surprise plea Monday at the first session of the tribunals set up after the U.S. Supreme Court struck down the Pentagon's previous efforts to try Guantanamo prisoners. The military said he could be sentenced this week and will likely be returned to Australia this year to serve his time there.

Hicks appeared focused as his Pentagon-appointed attorney told the judge that his client was pleading guilty to one of two counts of providing material support for terrorism. Asked by the judge if this was correct, Hicks said solemnly, "Yes, sir."

Hicks' father, Terry Hicks, told Australian Broadcasting Corp. radio on Tuesday he believed his son had pleaded guilty as part of a bargain with prosecutors that would get him out of the Guantanamo prison: "It's a way to get home, and he's told us he just wants to get home."

"He has been through five years of absolute hell," Terry Hicks added. "I think anyone in that position, if they were offered anything, I think they'd take it."

Hicks, a Muslim convert, allegedly attended Al Qaeda camps in Afghanistan, conducting surveillance on the British and American embassies as part of his training. But he remained on the margins once the U.S. invaded to oust the Taliban following the Sept. 11 attacks. He eventually joined Al Qaeda fighters hours before the front lines collapsed and was captured as he tried to flee, according to the U.S. military.

The count he pleaded guilty to says he intentionally provided support to a terror organization involved in hostilities against the United States. He denied the charge that he supported for preparation, or in carrying out, an act of terrorism.

Defense attorneys said a gag order by the military judge prevented them from discussing details of the plea until a sentence is announced and it could not be immediately determined whether there was a formal plea bargain.

Hicks' Australian lawyer, David McLeod, had said earlier his client was considering a plea deal.

"All of the options obviously have to be discussed, from not guilty and tough it out, through to 'How do I get out of here at the earliest opportunity,"' McLeod told reporters ahead of Monday's hearing.

A panel of military tribunal members convened for the Hicks case must travel to Guantanamo to approve any sentence, a development that could come this week.

"If I was a betting man, I'd say the odds are good" that Hicks will be home by the end of the year, Air Force Col. Morris Davis, the chief prosecutor for the Guantanamo tribunals, told reporters after Hicks entered his plea.

The charge carries a maximum penalty of life in prison, but Davis has said he would seek a sentence of about 20 years. He said the five years Hicks has spent at Guantanamo could be considered in the ultimate sentence.

In the days leading up to the hearing, defense attorneys said Hicks did not expect a fair trial and was severely depressed and considering a plea deal to end his five-year imprisonment at the U.S. naval base in Cuba.

The United States has agreed to let Hicks serve any sentence in Australia.

"This is the first step toward David returning to Australia," said McLeod.

Australian Foreign Minister Alexander Downer said he expected Hicks would return soon to Australia, where an outcry over his continued detention has cost Prime Minister John Howard support ahead of elections due this year.

"I am pleased for everybody's sake that this saga ... has come to a conclusion," Downer told Australian Broadcasting Corp. radio.

The United States is holding about 385 prisoners at Guantanamo. Among them is Khalid Sheikh Mohammed, an Al Qaeda member who during a so-called Combatant Status Review Tribunal earlier this month confessed to planning the Sept. 11 attacks and other terror acts. That military panel determined he was an enemy combatant who could later face charges.

Unlike the alleged terrorist mastermind, Hicks has been depicted by the U.S. military in its charge sheet as a minor figure.

Australian Sen. Bob Brown, leader of the minor opposition Greens party, said Hicks made the plea so he could get out of Guantanamo Bay and his guilt would remain in doubt.

"He's pleaded guilty but under circumstances that wouldn't hold up in an Australian court and that debate will fly home with Hicks," Brown said.

Hicks had asked for more lawyers to help defend him, but the judge, Marine Corps. Col. Ralph Kohlmann, instead ordered two civilian attorneys to leave the defense table, leaving the defendant with one attorney.

One of the civilian lawyers, Joshua Dratel, said he refused to sign an agreement to abide by tribunal rules because he was concerned the provisions did not allow him to meet with his client in private.

Hicks' military attorney, Marine Corps Maj. Michael Mori, challenged Kohlmann's impartiality, arguing that his participation in the previous round of military trials that the Supreme Court last year found to be illegal created the appearance of bias.

A challenge of the reconstituted tribunal system is pending before the Supreme Court. Lawyers for detainees have asked the high court to step in again and guarantee that the prisoners can challenge their confinement in U.S. courts.

Kohlmann ordered attorneys to attend a closed session Tuesday in a hilltop courthouse at Guantanamo to specify the acts to which Hicks is pleading guilty. The judge also will make sure Hicks understands the consequences of the plea, officials said.