Canada's fighter jets will end combat operations within the next two weeks and be replaced by an enlarged and riskier military training mission and a new humanitarian focus on the refugee crisis engulfing the region around Syria.

The expanded mission will see the number of Canadian special-forces trainers climb to 207 from 69, which Canada's top general warned will increase the risks of their being killed or wounded in firefights with Islamic State militants.

Prime Minister Justin Trudeau tried to play down the danger to Canadian soldiers, saying the revised military role does not authorize direct combat with the enemy.

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"This is an advise-and-assist mission that our trainers will be engaged in and, as I said many times throughout the campaign and my commitment to Canadians, this is a non-combat mission," Mr. Trudeau told a news conference.

However, General Jonathan Vance, Chief of the Defence Staff, said Canadian special forces will operate the same way they did under the mandate laid out by the former Conservative government.

These highly skilled commandos will go up to the front lines on training missions with Kurdish peshmerga fighters and will also paint targets for coalition air strikes.

"We want Canadians to know that we will be involved in engagements as we defend ourselves and those partners who we are working with," Gen. Vance later told reporters. "You put more people on the ground in a dangerous place, it is riskier over all."

Mr. Vance tried to avoid contradicting the Prime Minister, whose party was critical of the Conservative government for allowing Canadian commandos on the front lines. In 2015, one special-forces commando was killed and three others wounded in a friendly-fire incident on the Kurdish front.

"The Prime Minister has clearly described it as non-combat," Gen. Vance said. "In my view, it's a non-combat mission in that we are not the principal combatants here."

Mr. Trudeau, who telephoned U.S. President Barack Obama on Monday to explain Canada's revised role, announced Canada's six aging CF-18 fighter jets will cease air strikes by Feb. 22, fulfilling a key election pledge despite opposition at home and from allies of the U.S.-led coalition.

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"We are for what will be effective, not for what will make us feel good," Mr. Trudeau said. "We are confident that the training mission in Northern Iraq that we are now expanding is going to allow people in Northern Iraq to reclaim their communities, to be most effective in the fight against [IS]."

Under the reconfigured mission, Canada will keep its two CP-140 Aurora surveillance aircraft and Polaris CC-150 air-to-air refueller as part of the air-war operations.

The size of Canada's military mission will climb to 830 from 650 personnel, including medical teams with small helicopters and military experts to advise on targeting, strategic planning and intelligence.

Canada will also provide Iraqi security forces with small arms, ammunition and night-vision equipment. About 100 Canadian soldiers will be deployed to Lebanon and Jordan for training and advice.

The Canadian plan includes a substantial $1.1-billion in humanitarian and development aid to help countries such as Lebanon and Jordan cope with the flood of refugees. It includes $840-million for water, shelter, medicine and sanitation and $270-million for social services.

"Our plan will support the host governments and communities deliver adequate services, to rebuild infrastructure and create jobs, so that adults can earn a living and children can be children with hope for the future, rather than becoming recruitment targets for violent extremist groups," International Development Minister Marie-Claude Bibeau said.

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The new mission will be debated and voted on in Parliament. Its term will run until the end of March, 2017. The total cost of the military and humanitarian operations over the next three years will be $1.6-billion.

On Monday, interim Conservative leader Rona Ambrose denounced the Liberal government's withdrawal from the air war as a "step backward for Canada."

"This Prime Minister is taking a shameful step backward from our proud traditions by pulling our CF-18s and Canada out of a combat role against the greatest terror threat in the world," Ms. Ambrose said.

NDP Foreign Affairs critic Hélène Laverdière criticized the government for blurring the lines between combat and non-combat.

"We are concerned that the Liberal government has chosen to place Canadian Forces personnel deeper into an open-ended combat military mission in Iraq – a mission that fails to even define what success would look like," she said.

Mr. Trudeau's announcement comes two days before Defence Minister Harjit Singh Sajjan travels to Brussels for a NATO defence ministers' meeting that will focus on the Islamic State.

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Canada had been excluded from an earlier meeting in Paris, which the Conservative Party interpreted as a snub to Ottawa over its plans to pull its CF-18s out of the war.

On Monday, the Obama administration welcomed the revised Canadian role to the anti-IS campaign with carefully chosen comments that avoided any direct criticism of Mr. Trudeau's decision to end combat operations.

"The new Canadian commitment is in line with our current needs, including tripling their training mission in Northern Iraq and increasing their intelligence efforts," the U.S. State Department said.

However, White House spokesman Josh Earnest made clear that U.S. President Barack Obama may seek more from Canada.

"We going to have continuing discussions with the Canadians about additional steps they can take to further enhance our [counter-IS] efforts," Mr. Earnest said at the White House briefing. "Those new commitments are indicative of the kind of close relationship that the United States and Canada enjoy, particularly when it comes to our mutual national security."

The Pentagon also put a positive spin on the end of Canadian combat operations, saying U.S. Defence Secretary Ashton Carter "appreciates the decision by the Trudeau government to step up Canada's role."

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Defence analyst David Perry said even though Ottawa is scaling back its air operations, it is helping the coalition by providing Canadian intelligence and targeting experts at the main air base in Kuwait.

"We are enhancing the air combat of our allies because of the intelligence and targeting capabilities we are deploying. That's designed to help other people who actually fly the aircraft and drop the bombs," Mr. Perry said.

With a report from Paul Koring in Washington