OTTAWA -- Prime Minister Justin Trudeau accused the previous Conservative government of having endangered Canadian troops as he defended a recent clampdown on information about Canada's mission in Iraq.

The comments came during a sharp exchange in the House of Commons on Tuesday in which interim Conservative leader Rona Ambrose alleged the Liberals were keeping Canadians in the dark for "political reasons."

She alleged the Liberal government was trying to hide the fact that Canadian soldiers are actively fighting the Islamic State of Iraq and the Levant despite Trudeau's promise during last year's election campaign to end the combat mission in Iraq.

Military officers revealed during a rare briefing this month that Canadian special forces troops have been spending more time on the front lines and engaging in more firefights with ISIL forces.

But the military and government have refused to provide further details, including the number of incidents, what Canadian soldiers are doing on the front lines, and even how many troops are in Iraq.

Ambrose noted the Conservatives held more briefings and provided more details about the mission when they were in power.

"But the prime minister has changed that policy for political reasons," she said. "He promised to end a combat mission that he's actually expanding. Will the prime minister be transparent and resume these briefings so Canadians can know exactly what our men in uniform are facing?"

Trudeau acknowledged that his government, which was elected on a promise of greater transparency, was being more restrictive in terms of information about the campaign against ISIL.

But he defended it as necessary to protect Canadian soldiers.

"We have changed somewhat the approach that the previous government had," Trudeau said. "We will not put our men and women in the Canadian Forces in harm's way for communications purposes."

The exchange drew shouts from both sides of the aisle. It also marked an escalation in the battle between those calling for more transparency and those insisting on secrecy with regards to the Iraq mission.

That debate has been punctuated by the current operation to free the city of Mosul, which began last week and featured some of the fiercest fighting in Iraq since the U.S. invasion in 2003.

The government has said Canadian troops on the ground are supporting the offensive to retake the city of 1.2 million, ISIL's last bastion in Iraq, but refused to elaborate.

The only thing it has revealed is that a promised military hospital, which was intended to support the Mosul attack, has not yet arrived. Defence Minister Harjit Sajjan has blamed the Iraqi government in Baghdad for the delay, though he says it should arrive soon.

Meanwhile, several photos have emerged on social media showing Canadian special forces in Iraq. In one, two soldiers can be seen setting up an anti-tank missile system. Another shows Canadian troops manning vehicle-mounted machine guns behind a sand berm. It's unclear when or where the photos were taken.

Ambrose said Canadians shouldn't have to learn about the mission on Twitter.

The government also again refused to rule out the idea of Canadian troops being deployed into Syria to fight ISIL after Sajjan left the door open to such a mission on Monday.

"We are an important and committed partner to the international coalition against (ISIL)," Sajjan's parliamentary secretary, John McKay, said in response to a Conservative question. "We will assess the needs of the coalition as time goes on, but under this current mandate, our mission is focused in Iraq."