The Conservatives offered additional humanitarian aid Monday for the battle against ISIS, anticipating opposition MPs' arguments against sending Canadians into air combat in Iraq, but that failed to stem the criticism. 

Foreign Affairs Minister John Baird pledged up to $10 million to provide services and treatment for Syrian and Iraqi refugees who have been victims of sexual abuse as he kicked off debate.

Read the CBC News liveblog as MPs debate sending troops to Iraq

The House devoted most of the day Monday to discussing the government's plan to deploy six fighter jets and 600 troops in a six-month air combat mission against the Islamic State in Iraq and Syria, also known as ISIS. The Canadian mission would target ISIS in Iraq but not Syria, something the opposition NDP fears could change.

Baird also announced a joint Canada-U.K. assessment mission in Iraq to identify what else can be done to help victims of ISIS, as well as the deployment of an expert to work with the UN Human Rights Council on a fact-finding mission to Iraq.

NDP ​Leader Tom Mulcair moved to make changes to the government's Iraq motion, although Baird's announcement covered some of the requests contained in Mulcair's amendments.

The biggest change contained in the NDP amendment would be to block Canadian troops from any kind of combat in Iraq. It would also limit the mission to three months of weapons transportation and require the government go back to the House before extending the mission, whether to make it longer or to include Syria.

The government says the clock started on the six-month mission last Friday.

'Canada protects the vulnerable'

While the Conservatives argued it's impossible to curtail ISIS militancy without directly attacking its members, the NDP argued for a focus on humanitarian aid and the Liberals argued the government hasn't provided enough details on its plan.

Baird called on MPs to treat the issue soberly, but in the same speech made some pointed remarks about the Liberal Party's stance.

"My Canada protects the vulnerable. It challenges the aggressor. My Canada doesn’t leave all the heavy lifting to others," Baird said.

"There was a time when the Liberal Party believed in that."

Mulcair spent a significant part of his speech outlining the horrific violence perpetrated by Syrian leader Bashar al-Assad and questioned why Prime Minister Stephen Harper had left open the possibility of helping him fight ISIS in his country, should Assad request Canada's assistance.

"Why, Mr. Speaker, would we give credibility to a character like Bashar al-Assad?" Mulcair said.  

"That gives him a credibility he doesn't deserve. He's a genocidal maniac and we should not be giving him any credibility at all."

'Across the Rubicon'

Liberal foreign affairs critic Marc Garneau said Harper hasn't made enough of a case for a Canadian role in the combat mission in Iraq.

"The prime minister is taking us across the Rubicon by deciding on a combat mission," Garneau said. 

"Once a country makes that decision, there is no turning back the clock.... It is no simple matter to cross back over, and we all know this conflict is likely to last a long time.​"

The Liberals are also concerned, Garneau said, that there's no way to limit Canada's role once the country engages in the conflict.

Debate continues Tuesday, with the vote on the mission to fight ISIS set for Tuesday at 8:30 p.m. ET. The government isn't required to hold a vote on combat missions, but Harper pledged to do so.

Harper outlined last Friday the details of the Canadian contribution: up to six CF-18 fighter jets, two Aurora surveillance planes and one heavy-lift plane to carry equipment. The Canadian deployment will include approximately 600 personnel, and the mission will only fly over Iraq, unless the Syrian government invites Canada to bomb ISIS in its territory, too. The deployment will be limited to six months.