Canadian Armed Forces members are playing a modest but vital supporting role as the operation to retake Mosul, the last major stronghold of Islamic State militants in Iraq, gets under way.

How dangerous it might get for Canada's special forces soldiers will depend on whether the Kurdish troops they're advising are assigned a difficult role in reclaiming Mosul, which has been occupied by the Islamic State jihadis since June, 2014. It will also depend on whether their political masters in Ottawa allow Canadian soldiers to enter Mosul during what could be difficult block-by-block urban warfare.

Up to 210 Canadian special forces troops are advising Kurdish peshmerga fighters who are teaming up with Iraqi government forces, Sunni tribal fighters and Shia militias to encircle and take Mosul. The Trudeau government, which promised in the 2015 election campaign to end a combat role in Iraq, insists what soldiers are doing there is not combat even though Canadian special forces soldiers are guiding the Kurds from the front lines and exchanging fire with enemy troops from time to time.

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Right now, Canadian military advisers are with Kurdish unit commanders near the battlefront or in peshmerga encampments around Erbil, the capital of Iraqi Kurdistan which is 85 kilometres from Mosul, or farther south in Kirkuk, 175 kilometres from the IS stronghold.

Canadian generals last week warned the public that the environment in Iraq has grown more dangerous for Canada's soldiers as their task now focuses on advising the Kurds in battle rather than merely training them in open-air classrooms far back from the conflict.

Overhead, two Canadian spy planes, the CP-140 Auroras, are gathering intelligence that will be used by coalition planners to generate lists of Islamic State targets to be bombed. As well, the Royal Canadian Air Force's Polaris tanker is refuelling coalition warplanes conducting the bombing raids.

Not far from the front line – but not so close as to be in harm's way – up to 60 Canadians will be operating a field hospital to treat the wounded Kurds, Iraqi government forces or their allies. The Role 2 facility will not be big but will triage, resuscitate, treat and care for injured soldiers until they return to duty or are evacuated.

Ottawa is tight-lipped on the role that Canada's 21st Electronic Warfare Regiment is playing in Iraq. The military has reportedly deployed members of this regiment, which can intercept and decipher enemy communications.

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Canadian Defence Minister Harjit Sajjan was tight-lipped Monday when asked exactly where Canada's soldiers are located on the battlefield, citing operational security.

"For force protection, I won't tell you exactly where they will be, but they will be always in an advise-and-assist mission. They will always be within [or] behind the front lines to conduct their work and … they will always have the right tools and abilities to be able to protect themselves if needed."

The fight to retake Mosul is being billed as the largest military effort in Iraq since the United States withdrew its combat forces in 2011.

David Perry, a senior analyst with the Canadian Global Affairs Institute, said Canadians are also helping to assemble targeting "packages" for air commanders who are selecting bombing targets.

He said it's possible the fight to retake Mosul could end up going relatively slowly because the coalition will be trying to avoid killing civilians inside the city. Mr. Perry said estimates of civilians inside Mosul are as high as one million people.

A U.S.-led air campaign has helped push Islamic State from much of the territory it held, but 4,000 to 8,000 fighters are thought to remain in Mosul.

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With a report from Reuters