Prosecutors and defence lawyers have been discussing a possible plea bargain for a young Canadian held on terrorism charges at the US military detention facility at Guantanamo Bay, a defence lawyer has said.

Omar Khadr in this file photo. Jennifer Turner, a human rights researcher with the American Civil Liberties Union, said Khadr's case would be the first prosecution in American history of an alleged child soldier and a "huge embarrassment" for the Obama administration. "It would be breaking with international practise too. Under international law, children who have been recruited for war are considered victims," she told Al Jazeera. As pre-trial hearings in Omar Khadr's case began, a defence lawyer said there had been negotiations over a deal that would allow Khadr to plead guilty to reduced charges in exchange for leniency.

Barry Coburn said on Tuesday evening that plea discussions were ongoing with prosecutors.

"As of right now there is no deal. We are always open to discussion and we're hopeful of reaching a resolution," Coburn told reporters at Guantanamo Bay.

The Toronto Star newspaper, citing unidentified sources, said Khadr had rejected an offer that would have limited his sentence to five more years in custody at Guantanamo or a US prison.

Khadr could be jailed for life if convicted of all five charges against him, which include murder and conspiring with al-Qaeda.

Controversial case

Al Jazeera's Monica Villamizar, reporting from Guantanamo, said the prosecution appeared to be seeking to avoid a controversial trial as Khadr is classified as a "child soldier" under international law and subject to certain protections.

"This shows that the prosecution maybe believe that they do not have a case that is as strong as they wish and they want to try to come up with some solution before the trial date," she said.

Khadr was arrested in Afghanistan in July 2002, when he was 15 years old.

He is accused of killing a US soldier when he threw a grenade at the end of a four-hour US bombardment of an al-Qaeda compound in the eastern Afghan city of Khost.

He has been held at Guantanamo since October 2002 and is now 23.

The hearing on Wednesday was to determine if Khadr's alleged confessions to interrogators can be used as evidence against him at his trial in July.

Treatment claims

Khadr claims he was treated badly while in detention, first at a military camp in Bagram, Afghanistan, and later at Guantanamo, and that he was tortured and forced into confessing that he used a grenade to kill the US soldier.

Defence lawyers say that during at least 142 interrogations in Afghanistan and Guantanamo, Khadr was beaten, doused in freezing water, spat on, chained in painful positions, forced to urinate on himself, terrorised by barking dogs, subjected to flashing lights and sleep deprivation and threatened with rape.

Prosecutors contend Khadr was treated humanely and fabricated the abuse allegations.

Captain David Iglesias, the legal adviser for the prosecution, told Al Jazeera that up to 30 defence and prosecution witnesses would testify on whether Khadr's statements were voluntary or tainted by torture or other improper conduct by US personnel.

"I am confident that with the new rules there is due process, there are greater rights afforded to detainees," he said.

"Specifically it's harder to use hearsay evidence on both sides, there is greater difficulty for prosecution to introduce evidence or statements derived not just from alleged torture but also from humiliating or degrading treatment ... there are greater counsel rights, greater appellate rights.

"As a former federal prosecutor I'm convinced that this more than meets the minimum standards of due process," he said, adding that US law permits the prosecution of juveniles accused of violent crimes.

Iglesias said that legal rules prevented him from commenting on whether negotiations of a plea bargain in Khadr's case were being held.

In October, Obama signed a new law prohibiting the use of evidence obtained through coercion and making it harder to use hearsay evidence in the Guantanamo tribunals.

The Pentagon rule manual implementing the changes, however, was only completed and signed by Robert Gates, the US defence secretary, on Tuesday night.

'Huge embarrassment'

Khadr's case is the first to be heard since Barack Obama, the US president, reformed the trial system at Guantanamo.

He is one of six prisoners at Guantanamo Bay that the Obama administration has designated for a military hearing.

Jennifer Turner, a human rights researcher with the American Civil Liberties Union, said Khadr's case would be the first prosecution in American history of an alleged child soldier and a "huge embarrassment" for the Obama administration.

"It would be breaking with international practise too. Under international law, children who have been recruited for war are considered victims," she told Al Jazeera. 

"[Khadr] was taken by his family to a war zone and he has now been abused for years. He really should be treated as a candidate for rehabilitation and integration first rather than abuse and prosecution as the American government has done."

Toronto-born Khadr is the only remaining westerner held at Guantanamo, and the youngest among the 183 detainees charged with murder, conspiracy and support of terrorism.

His father, Ahmed Said Khadr, allegedly an al-Qaeda fighter and financier, was killed during a raid by Pakistani forces in 2003.

One of his brothers, Abdullah Khadr, is being held in Canada on a US extradition warrant, accused of supplying weapons to al-Qaeda, while another brother has said that the family stayed with Osama bin Laden, the leader of al-Qaeda.