Canada is heading to war in Iraq after Stephen Harper's announcement that he intends to deploy jet fighters to join coalition air strikes against Islamic State militants for as long as six months, but vowing not to be dragged into a "prolonged quagmire."

A parliamentary vote on the combat mission will take place Monday in the Commons, but it's expected to pass easily given the governing Conservatives' majority. The motion to be debated rules out the use of Canadian ground troops, but it also extends the current deployment of 26 military advisers to northern Iraq for as long as half a year more.

Within a matter of weeks, six CF-18 fighters, a refuelling aircraft and two surveillance planes will head to a staging base within range of Iraq and join the U.S.-led aerial campaign against the jihadi extremists that have cut a swath of destruction across the region.

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They will be accompanied by about 600 Canadian Armed Forces personnel. Together with the military advisers, whose deployment is authorized to increase to 69, the total number could rise to as many as 670 deployed – the largest overseas mission since Afghanistan.

Further, Ottawa announced that Public Safety Minister Steven Blaney will shortly introduce measures to strengthen the ability of law enforcement agencies to monitor "aspiring terrorists" and prevent their return to Canada, as well as give them greater tools to charge and prosecute them if they return.

Mr. Harper is also leaving the door open to launching air strikes in Syria, next door to Iraq.

Polls suggest close to two-third of Canadians back the use of Ottawa's fighter jets against Islamic State forces.

But the Tories' combat deployment was flatly rejected by opposition party leaders who said Canada should focus on humanitarian aid instead.

Mr. Harper justified the combat mission by saying Canada must protect itself from a jihadi group that has threatened this country and its allies, and also has a moral obligation to degrade the Islamic State's capacity to commit atrocities against the people in Iraq and Syria.

"It has tortured and beheaded children. It has raped and sold women into slavery. It has slaughtered minorities, captured prisoners, and innocent civilians … whose only crime is being or thinking differently," the Prime Minister said.

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Canada's deployment was announced shortly before news broke of another apparent beheading of a Westerner by Islamic militants. An Internet video released Friday purports to show an Islamic State fighter beheading British aid worker Alan Henning. The video ended with a militant threatening to kill another man identified as an American.

Mr. Harper said Canada's combat objective is to work with allies to "significantly degrade the capabilities" of the jihadist extremists to engage in military operations and to operate bases in plain sight. He acknowledged that joint military action would not likely eliminate the Islamic State, but nevertheless aims to significantly reduce its power.

The Conservative government's air-strike motion to be debated Monday differs from similar authorization approved by the U.K. Parliament on Sept. 26. The U.K. motion forbids air strikes in Syria and says another vote would need to be held before these could take place.

Mr. Harper put Canadians on notice that Canada could also launch air strikes in Syria, as the U.S. is doing, but said this country would only do so if it had the "clear support" of the Syrian government.

The government motion asks MPs to "recognize that the leadership of the terrorist group known as the Islamic State … has called on its members to target Canada and Canadians at home and abroad."

The Prime Minister said the military measures the government is planning do not preclude offering humanitarian aid to Iraq. However, he did not elaborate on any new plans to help refugees and displaced people in the region, and did not indicate what additional assistance Canada might provide.

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The mission

The Canadian government will join an international coalition in launching air strikes against Islamic State forces in Iraq.

The Islamic State "intends to launch a terrorist jihad not merely against the region, but on a global basis," Prime Minister Stephen Harper told the House of Commons Friday. "Indeed, it has specifically targeted Canada and Canadians, urging supporters to attack 'disbelieving Canadians in any manner,' vowing that we should not feel secure, even in our homes."

The assets

Canada's air combat mission will include up to six CF-18 fighter jets, one air-to-air refuelling aircraft, two Aurora surveillance aircraft, and the necessary air crews and support personnel. The planes will deploy within three weeks, once Canada has worked out the logistics and secured a staging base.

They will be accompanied by close to 700 Canadian Armed Forces personnel in the largest mission abroad in several years.

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The Conservatives are explicitly vowing not to deploy ground troops in this battle.

The objective

The goal is to work with allies to "significantly degrade the capabilities" of the jihadist extremists to engage in military operations and operate bases in plain sight.

Mr. Harper said while joint military action won't eliminate the Islamic State, it aims to significantly reduce its power.

The timeline

The air combat mission will last up to six months. As well, Ottawa is extending the Sept. 5 deployment of military advisers – 26 elite special forces soldiers to help Iraq and Kurdish fighters – for up to half a year.

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The scope

The theatre of war for Canadian air strikes is Iraq but could expand to Syria if Ottawa had the "clear support" of the Syrian government. Canada is acting in tandem with about a dozen other allies including the United States and Britain.

With a report from The Associated Press