OTTAWA - The federal public safety minister suggests an "explosive cocktail" of mental health problems, drug addiction and extremist ideology prompted the recent killing of a soldier in Ottawa.

Steven Blaney told a security conference Tuesday that Canada must be vigilant about the threat posed by people who become radicalized "for whatever reason."

Blaney's remarks introduced a thread of subtlety into the federal characterization of the deadly shooting of Cpl. Nathan Cirillo at the National War Memorial.

Prime Minister Stephen Harper was quick to label the Oct. 22 shooting an act of terrorism.

It soon after emerged that the killer, Michael Zehaf Bibeau, had abused drugs, spent time in homeless shelters and displayed erratic behaviour.

The RCMP says a video the man recorded before the shooting indicates his actions were rooted in his Islamic religious beliefs and opinion of Canada's foreign policy.

NDP Leader Tom Mulcair maintains the Ottawa shooting was a criminal act, but he does not consider it terrorism.

In a Facebook posting this week, Cirillo's girlfriend, Andrea Polko, said Canadians should be talking about "the dismal state of mental health care in our country" and the need for effective treatment programs that target "the real" source of the tragedy.

Two days before the attack, a man known to the RCMP for extremist views killed one soldier and injured another with a car in St-Jean-sur-Richelieu, Que.

"These terrible acts underscore the need for Canada to remain vigilant against terrorist attacks by individuals who become radicalized to violence for whatever reason," Blaney said Tuesday.

"We saw the explosive cocktail that mental health, drug addiction and ideology — extremist-inspired — can provide," he told the audience of security professionals. "So we need to adapt, adjust and reach out — take this opportunity as Canadians to be prepared. And also ... work with other countries that are facing the same challenges."

In the House of Commons following the speech, Blaney's remarks on the two deaths were decidedly less nuanced. He said it was important to call "a spade a spade" and acknowledge that the two October events were terrorist attacks.

Blaney urged passage of a government bill — crafted well before the two attacks — that would ensure the ability of the Canadian Security Intelligence Service to track suspects overseas and provide blanket protection to the spy agency's informants.

Blaney said Canada faces "a serious terrorist threat — one we must address with strong measures."

The New Democrats and Liberals expressed support for sending the bill to committee, but stressed a need for extensive debate. The opposition parties also decried the lack of new accountability measures in the legislation.

"We have many serious questions to ask the government," said NDP public safety critic Randall Garrison.

He called on the Conservatives to reach out to communities on prevention and early-intervention strategies intended to deal with radicalism.

Liberal public safety critic Wayne Easter said the government should introduce accompanying measures "to provide proper parliamentary oversight" of security agencies.

The Conservatives have resisted opposition calls to bolster review of intelligence services — including a private bill sponsored by Liberal MP Joyce Murray to increase scrutiny of Canada’s electronic spy agency and create a full-fledged national security committee of parliamentarians.

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