Omar Khadr, seen in a courtroom sketch, was captured by U.S. troops in Afghanistan in 2002, when he was 15. (Janet Hamlin/Pool/Associated Press)

The judge presiding over Omar Khadr's military commission proceedings issued an order Tuesday that the hearings, abruptly halted by U.S. President Barack Obama in January, are to go ahead on June 1.

The order from Col. Patrick Parrish came on the eve of a UN Security Council debate on the issue of child soldiers, an event Khadr's lawyers planned to piggyback on with a news conference highlighting his plight.

"The commission is setting June 1, 2009, as the next hearing date," Parrish wrote. "This notice will give all parties sufficient time to prepare."

Khadr, now 22, is accused of throwing a hand grenade that killed an American special forces soldier following a four-hour firefight in Afghanistan in July 2002.

The Toronto-born Khadr was 15 at the time.

Child soldiers must be treated like victims: UN

Cmdr. Walter Ruiz, one of Khadr's Pentagon-appointed lawyers, said he planned at Wednesday's news conference in New York to stress the age issue and that Washington has violated an international child-welfare treaty.

The Optional Protocol to the UN Convention on the Rights of the Child essentially obliges signatories to treat soldiers under the age of 18 as victims in need of rehabilitation and reintegration.

"It would be adding insult to injury to prosecute him on top of the fact that we basically failed to comply with every provision of the Optional Protocol," Ruiz said Tuesday from his office in Washington, D.C.

"This is an issue of monumental importance, particularly because the decisions that this administration makes are going to be in essence setting an important precedent."

Recommendation due May 20

Khadr's fate is currently under consideration by a presidential review panel, which is due to make recommendations by May 20. Obama halted all military-commission cases in January pending the review.

Khadr's lawyers want the panel to recommend his repatriation to Canada, arguing there's no way he could be legitimately prosecuted in light of the United States' obligations under the child-soldier treaty, which it ratified in 2002.

Last week, a Federal Court judge in Canada ordered Prime Minister Stephen Harper to press for Khadr's return to Canada, in part because Ottawa had also failed to live up to its international treaty obligations.

Khadr's lawyers immediately forwarded that decision to the presidential review committee as an addendum to the materials filed ahead of the April 15 deadline for submissions.

About 16 career prosecutors with the U.S. Department of Justice are sifting through the cases of about 245 people still held at the infamous prison at Guantanamo Bay, Cuba.

Ruiz said panel members had indicated they were serious about meeting the May 20 deadline and that Khadr's case was among those they considered of highest importance.

"This is the time for the new administration to act and bring us back into compliance," Ruiz said.

"Our thought at this time is that: If not now, when?"

Of the 775 prisoners who have been held at Guantanamo Bay at one time or another since 2001, about 525 were released without charge, many after years of detention, and two have been convicted of offences.

Australian David Hicks pleaded guilty in March 2007 to providing support for terrorism and was sent back to his home country to serve the remaining nine months of a seven-year sentence, while Salim Hamdan, Osama bin Laden's one-time chauffeur, was found guilty last August of the same crime and sentenced to a further five months in prison on top of time served.

A spate of organizations, from Amnesty International to the Red Cross to the FBI and CIA, have acknowledged that many inmates at Guantanamo were tortured.