The entrance to Camp Delta at Guantanamo Bay, Cuba, where Omar Khadr has been detained since 2002. (Colin Perkel/Canadian Press)The Canadian government has agreed to Omar Khadr's plea deal that allows him to return to Canada to serve the rest of his sentence after spending a maximum of one year in prison in Guantanamo Bay, Cuba, his lawyer says.

The Toronto-born Khadr pleaded guilty Monday to the five charges against him, including murder and supporting terrorism in Afghanistan, as part of a plea agreement with prosecutors at the U.S. military commission at Guantanamo Bay.

Khadr's Canadian lawyer, Dennis Edney, said Khadr will serve no more than eight years in prison as part of the plea deal and then be subject to parole board conditions upon his release.

Edney, in a phone interview with the CBC from Guantanamo Bay, labelled the plea deal "a piece of paper" and said his client "would have confessed to anything, including the killing of John F. Kennedy, just to get out of this hellhole."

"Had Omar refused, then he was faced with an unfair trial based on evidence that would be inadmissible in a real court and the potential of life in prison in Guantanamo Bay," Edney said.

"We supported this decision, and we would have done the same thing with his position."

Sentencing expected Tuesday

Military judge Col. Patrick Parrish accepted Khadr's pleas and told him he will be eligible to apply for transfer to a Canadian prison after serving one year of his sentence in the United States or a U.S. detention facility.

In response to the plea agreement, Prime Minister Stephen Harper's spokesman, Dimitri Soudas, would only say the case is a "matter between Mr. Khadr and the U.S. government."

The comment echoed exactly that of a spokesperson for Foreign Affairs Minister Lawrence Cannon.

"We have no further comment," Catherine Loubier, Cannon's director of communications, added in an email.

The 24-year-old Khadr is expected to be sentenced Tuesday by a jury of seven military officers.

In a sketch by courtroom artist Janet Hamlin, reviewed by a U.S. Department of Defence official, U.S. Air Force Capt Michael Grant swears in Omar Khadr, right, on Monday in Guantanamo Bay. (Janet Hamlin/Associated Press)

Chief prosecutor Capt. John Murphy welcomed the plea, saying "it removes any doubt from what happened."

"Omar Khadr stands convicted of being a murderer and also of being an al-Qaeda terrorist," Murphy told reporters. "And the evidence did not come from a contested trial. It came from a source that the law recognizes as the most powerful evidence known from the law, and that is his own words."

Parrish said details of the plea deal would not be released until jurors have had a chance to review them.

Khadr had earlier maintained he would never confess to throwing the grenade that killed a U.S. soldier in Afghanistan in July 2002. U.S. officials allege he did so after an attack by U.S. forces on a suspected al-Qaeda compound. Sgt. Christopher Speer was killed and another soldier was wounded.

Shortly after 9 a.m. ET on Monday, Khadr withdrew his previous pleas of not guilty to the charges, including murder in violation of the laws of war, attempted murder in violation of the laws of war, conspiracy, providing material support to terrorists and spying.

Parrish asked Khadr if anyone had forced him to change his pleas, to which Khadr answered: "No."

Parrish then questioned Khadr about each of the charges against him. Asked if he had killed Speer in 2002, Khadr answered, quietly, "Yes." When asked if it was true that he conspired with Osama bin Laden and al-Qaeda, he also answered "Yes."

Khadr 'abandoned': NDP's Harris

U.S. Navy Capt. John Murphy, chief prosecutor for the military commissions, speaks to media after Canadian Omar Khadr pleaded guilty to war crimes at Guantanamo Bay, Cuba, on Monday. (Colin Perkel/Canadian Press)

His defence and opposition politicians in Canada have argued Khadr was a child at the time of the killing and should be treated according to international law, which provides that child soldiers be rehabilitated, not punished.

NDP defence critic Jack Harris said the Canadian government's response to Khadr's case was "totally inadequate" and goes against human rights and international law because he was a child soldier.

Canada, he told reporters outside the House of Commons, is the "only country in the world who abandoned" a citizen in Guantanamo Bay.

NDP Leader Jack Layton told CBC's Power & Politics with Evan Solomon, "This government doesn't seem to pay any attention to those issues. We think that's unfortunate and wrong. No wonder the world is looking askance at Canada on the international stage, such as we saw with the UN vote." (He was referring to Canada's failure to win a seat on the UN Security Council earlier this month.)

Murphy, however, said Monday's pleas put to rest "the long-standing argument by some that Khadr is a victim.

"Omar Khadr is not a victim. He's not a child soldier. He's not someone whose conviction is not the product of any abuse. He's a murderer," Murphy said.

The federal government has refused to intervene on Khadr's behalf to have him removed from Guantanamo Bay and returned to Canada. Khadr has been held at the high-security U.S. detention facility since 2002, and is the only Westerner still incarcerated there.

With files from the CBC's Derek Stoffel and The Canadian Press