A man who was shot and killed by police after he struck two members of the Canadian military with his car was "clearly linked to terrorist ideology", officials said.
One of two soldiers hit by a car in a city near Montreal died from his injuries.
Public safety minister Steven Blaney called the attack a "terrible act of violence against our country, against our military and against our values" and "clearly linked to terrorist ideology".
Mr Blaney did not discuss whether or not authorities believed the man, a recent convert to Islam, acted on his own.
The suspect, Martin Couture Rouleau, 25, was shot on Monday by police following a car chase and later died.
An official familiar with the case confirmed the suspect's name and that he had fallen under the influence of radical Islam.
Royal Canadian Mounted Police spokesman David Falls said the suspect "was known to federal authorities" and "authorities were concerned that he had become radicalised".
Mr Blaney and police declined to provide further details, citing the ongoing investigation.
There was no answer at Rouleau's single-storey white brick home in Saint-Jean-sur-Richelieu, Quebec, on Tuesday morning, and no sign of police.
Neighbour Daniel Fortin said he had known Rouleau, who lived with his father, since he was a child.
Mr Fortin said over the past year or so, Rouleau grew out his beard and began wearing loose-fitting Muslim clothing but that he never felt threatened by him.
Mr Fortin said Roleau's father was worried as he became increasingly radicalised and "tried everything" to help him.
Another neighbour, who did not want to be named, said she did not know the family well but saw police visit the home on more than one occasion over the past few months.
Quebec provincial police Lt Michel Brunet said the suspect fled the scene of the attack and was pursued by police for about four kilometres (2.5 miles) before he lost control of the car, which rolled over several times. Police shot him after he exited the car.
Mr Brunet said they found a knife on the ground but he could not say if the suspect had it in his hand when police opened fire. Television images showed a large knife in the grass near the flipped-over car.
Mr Brunet said he could not say whether the soldiers were wearing uniforms at the time they were struck.
Canadian prime minister Stephen Harper was briefed about the incident by the head of Canada's national police force, the head of the military and his national security adviser.
Mr Harper said in parliament that he was aware of the reports and called them "extremely troubling".
"First and foremost our thoughts and prayers are with the victims and their families; we're closely monitoring the situation and obviously we will make available all of the resources of the federal government," Mr Harper said.
The case is similar to one in London last year in which an al Qaida-inspired extremist and another man ran over a soldier with a car before hacking the off-duty soldier to death.
Images of Michael Adebolajo, 29, holding a butcher's knife and cleaver with bloodied hands in the moments after the May 2013 killing of Fusilier Lee Rigby shocked people around the world and sparked fears of Islamist terrorism in Britain.
The Islamic State group has urged supporters to carry out attacks against Western countries, including Canada, that are participating in the US-led coalition fighting the militants who have taken over large swathes of territory in Iraq and Syria. Six Canadian fighter jets are set to depart for the region soon.
It was not known whether the suspect in the Quebec attack had any ties to Islamic militant groups.