Protesters rallied at the Peace Arch border crossing south of Vancouver on Tuesday morning against a Federal Court decision to deport Robin Long. (CBC)

American war deserter Robin Long is being returned to the units he deserted at Fort Carson in Colorado, a U.S. army spokesman said Tuesday.

Long, who fled to Canada in 2005, was deported Tuesday morning from British Columbia and was at one point being held at Fort Lewis in Washington State. There's no indication when the 25-year-old will be taken to Colorado.

"What's going to happen is he's going to be sent to Fort Carson [in] Colorado, where his units commander will have ultimate discretion on what's going to happen based on the fact in front of him," U.S. army spokesman Ryan Brus told CBC News Tuesday.

Robin Long says he has been trying to gain refugee status in Canada because he believes he would go to jail if sent back to the U.S. (CBC)

Meanwhile, a former U.S. army judge advocate general said Tuesday he doesn't believe Long's commander will push for severe punishment in order to send a message to the troops pondering desertion.

Michael Nardotti, now a lawyer, said Canada's deportation has already delivered a strong message.

"The more important message here is that Canada, which used to be considered an option, is not — at least not now," Nardotti told CBC News.

A Federal Court judge in Vancouver on Monday rejected Long's application for a stay of his deportation order, ending Canada's long-standing status as a place of sanctuary for war resisters.

That's the message the Harper government intended to send to the U.S., said Michael Byers, an international law expert.

Deserters will go underground in Canada: law expert

"What's happening now with the deportation of Robin Long is entirely consistent with the Harper government's refusal to repatriate [Guantanamo Bay prisoner and Canadian citizen] Omar Khadr," Byer said Tuesday.

"It's entirely consistent to seek assurances that Canadians on death row will not be executed. It's a reflection of a dramatic change in Canadian foreign policy on human rights."

Byers said while Long's deportation may be a gift from Canada to the Bush administration, which is struggling with the problem of desertion, it won't stop the flow of Iraq war deserters to Canada.

The deserters will only go underground, rather than conduct legal fights in public, Byers said.

Long settled in Marathon, Ont., with his partner and their small child when he came to Canada three years ago. He applied for refugee status in Canada for fear that he would suffer harm if he was sent back home.

He then decided to go to B.C. to work. When the Canada Border Services Agency didn't get a response in Ontario for an interview, a Canada-wide warrant for his arrest was issued.

Citizenship and Immigration Canada was willing to offer Long a pre-removal risk assessment in Ontario, but he left the province, leaving no forwarding address. The assessment evaluates the risk a refugee claimant will face if he or she is to be sent back to the originating country.

Long was arrested in Nelson, B.C., last October.

Protesters rallied on Tuesday morning at the Peace Arch border crossing, south of Vancouver, to show their anger at the Federal Court decision to deport Long.

But, by noon, Canada Border Services spokeswoman Shakila Manzoor confirmed Long had already been removed from the country and handed over to the U.S. authorities. Citing privacy reasons, she would not release any other details of when, how or where he was sent.