GUANTANAMO BAY, Cuba - Omar Khadr, forced to choose between standing his ground in the "hell hole" of Guantanamo Bay and conceding defeat so he might one day return to Canada, opted for the latter Monday as he admitted killing a U.S. special forces soldier in Afghanistan eight years ago, when he was just 15.

After years of defiantly maintaining his innocence and refusing to acknowledge the controversial system of military justice that has held him captive since 2002, the Toronto-born terror suspect quietly pleaded guilty to five war-crimes charges, part of a deal that could see him return to Canadian soil in 12 months.

Shortly after the court pronounced him guilty, those in Khadr's corner lined up to denounce the system that convicted him.

"In our view, it's all a fiction," said Dennis Edney, one of Khadr's Canadian lawyers. "In our view, Mr. Khadr is innocent."

In the end, Edney said, Khadr was forced to choose between the chance to serve part of his sentence in Canada and the likelihood that he'd remain in the "hell hole" of Guantanamo Bay indefinitely, fighting against an "illegal process" where the odds were stacked against him.

However, Capt. John Murphy — the lead American prosecutor at Gitmo — took a different view, saying the U.S. had now proven to the world that Khadr was an al-Qaida terrorist and a killer.

"The evidence did not come from a contested trial," Murphy said.

"It came from a source that the law recognizes as the most powerful evidence known to the law, and that is his own words."

In a 50-paragraph agreed statement of facts, Khadr admitted his guilt on all five charges. The statement was to remain sealed until jurors get a chance to review it on Tuesday.

It was an abrupt about-face for the 24-year-old Khadr, who has long denied throwing the grenade that killed U.S. Army Sgt. 1st Class Christopher Speer during a firefight in Afghanistan in 2002, when the American retaliation for the terrorist attacks of Sept. 11, 2001, was less than a year old.

Presiding judge Col. Patrick Parrish pronounced Khadr guilty after carefully making sure the accused, who attended the hearing clad in a suit and tie, understood what was happening. Khadr hung his head at times, looking subdued.

"Has anyone forced you to enter into this stipulation?" Parrish asked.

"No," Khadr answered softly.

And later: "It's your voluntary decision to continue with the plea of guilty?" Parrish asked. "Yes," came the reply.

As Khadr entered his plea, Speer's widow Tabitha, who is scheduled to testify during this week's sentencing hearings, wept quietly.

Under the terms of his plea agreement, the U.S. would support Khadr's transfer to Canada after one more year in an American prison. Approval of that transfer rests with the Canadian government, and any sentence served in Canada would be under Canada's laws and system, Parrish noted.

Khadr would likely be eligible for parole from the moment he set foot on Canadian soil.

While there was no guarantee that Khadr's wish to return to Canada would be granted, Edney suggested Ottawa has signalled it intends to allow the transfer to proceed.

"Canada's language is sufficiently satisfactory ... that it will take Omar Khadr back after one year," he said. "The American language is even stronger: they very clearly wish Omar Khadr to return home to Canada."

Reached at the family home in east-end Toronto, members of Khadr's family — long a subject of controversy in Canada for their purported ties to al-Qaida — refused to comment.

Foreign Affairs Minister Lawrence Cannon refused to talk about the government's position on a possible transfer, although he did make its position on Khadr abundantly clear.

"Mr. Khadr pleaded guilty to murder in violation of the laws of war, attempted murder in violation of the laws of war, as well as providing material support for terrorism and spying, as well as conspiracy," Cannon said in response to a question in the House of Commons.

"The media are reporting that Mr. Khadr also publicly acknowledged that he was a member of al-Qaida, that he planted roadside bombs and that he knew he was attacking civilians. The matter is between the U.S. government and Mr. Khadr's lawyers and we have no further comment."

Justice Minister Vic Toews had little to add, except to say that if Khadr does indeed apply for a transfer, it will be handled by the book.

"I haven't made any decision," Toews said. "Any application made to the government, that's my responsibility under the International Transfer of Offenders Act, and I make any determinations on that in accordance with law."

Parrish said the diplomatic notes exchanged between Washington and Ottawa would be released along with the plea-bargain terms once jurors have delivered their sentence.

Khadr's plea was a stark contrast to the defiance he has shown in previous court appearances, most notably in July when he told the court he would agree to no deals. Pleading guilty, he said at the time, would "give an excuse to the government for torturing me and abusing me as a child."

Under military commission rules, sentences must be imposed by a jury.

The seven-officer panel of jurors, who flew to the remote military base in Cuba on Monday, will be free to impose on Khadr any sentence up to life in prison. Khadr, however, will serve only the lesser of that sentence or what's in the plea deal, said to be eight years.

Former U.S. sergeant Layne Morris, who was partly blinded in one eye during the firefight in which Khadr was captured and Speer was killed, said he was gratified to hear the guilty plea, but worried about the sentence.

"Do I think another eight years is enough? No I don't," Morris said. "Do I have a figure in mind that will suddenly satisfy me and I can live out the rest of my life in peace? No."

Lt. Col. Jon Jackson, the Pentagon-appointed lawyer for Khadr whose sudden illness and courtroom collapse halted the trial in August, said he would do his best to get his client the lightest possible sentence.

"During the next several days, I look forward to proving to the panel and the world that Omar Khadr is a kind, compassionate, and decent young man who deserves a first chance at a meaningful life," Jackson told The Canadian Press.

The plea agreement obviates the need for the first contested trial under the military commission system, which human rights and legal groups in the U.S. and around the world have denounced as illegitimate.

Even the U.S. Supreme Court has ruled a previous version unconstitutional, prompting President Barack Obama to rewrite the rules that have not yet been properly contested in American courts.

Khadr has begun the final chapter in a long journey through a "labyrinth of injustice," said Alex Neve, head of Amnesty International Canada, who was on hand to observe the proceedings.

"That troubling reality that so many human rights concerns remain untouched and unresolved hangs over all of this like a dark shadow."