Liberal senator and ex-general Romeo Dallaire is calling on president-elect Barack Obama to stop the war crimes trial of Omar Khadr and return him to Canadian custody.

Khadr, the 22-year-old Canadian citizen who has spent six years in custody on charges that he killed a U.S. soldier in Afghanistan in July 2002, is the only western citizen still being held in Guantanamo Bay. Only 15 years old when he was first taken into custody, Khadr has still not been convicted any crime.

On Monday, Dallaire renewed his call for Khadr to be returned to Canadian custody and he wants Obama to play a role in making that happen.

It is Dallaire's hope that the incoming American president will move quickly to get Khadr returned to Canada, where Canadian laws will treat Khadr as a child soldier who can still be reformed.

"It's absolutely crucial that we do have a decision from him (Obama) before the trial actually starts," he told CTV's Canada AM on Monday from Washington.

The retired lieutenant-general said it is his impression that the president-elect is "keen" on closing down Guantanamo Bay.

Obama has publicly said that he intends to close Guantanamo Bay, but has also signalled it will be a difficult process to undertake.

Dallaire said he met with Congressional leaders last August and that many supported having Khadr handed over to Canadian officials.

Khadr's war crimes trial is scheduled to begin Jan. 26, only six days after Obama's inauguration.

Dallaire, along with other human rights activists, held a news conference in Washington on Monday morning to discuss the issue.

"The reason I'm down here is because I've gotten nowhere with the Canadian government," Dallaire told reporters in Washington on Monday.

He said that it would be in the president-elect's best interests to send Khadr back to Canada.

"If we take Omar Khadr back, we take one of Obama's problems away," Dallaire said.

"I mean, we alleviate the situation for him where he doesn't have to look at a case of a Canadian child soldier being prosecuted in a process that is considered to be inappropriate."

Dallaire told Canada AM "the stumbling block" on the Khadr issue has been Prime Minister Stephen Harper, who has said the accused Canadian must face the American legal system that is holding him.

But Dallaire argues that it is not the American legal system that Khadr is facing, but "an artificially-created, ad-hoc system, military-based system that the United States Supreme Court has found to be illegal in process" at Guantanamo Bay.

While many other countries have stepped forward to extricate their citizens from the controversial system in place at Guantanamo Bay, Canada has done little to intervene in Khadr's case, Dallaire said.

"Internationally, other countries have pulled their people out of this process in other to move them through...their own proper judicial process," he said.

"Or, in the case of child soldiers, as we're doing in Afghanistan, we try to bring them back, rehabilitate them and reintegrate them into our society."

Dallaire has long argued that Khadr is a child soldier who deserves the same treatment that Canada has devoted to other child soldiers around the world.

With files from The Canadian Press