Canada will not be intimidated by a pair of attacks that killed two soldiers this week, Prime Minister Stephen Harper said on Wednesday, adding that security agencies would do everything needed to counter threats to the country.

"Let there be no misunderstanding. We will not be intimidated. Canada will never be intimidated," Harper said in a brief address to the nation.

"In fact, this will lead us to strengthen our resolve and redouble our efforts - and those of our national security agencies - to take all necessary steps to identify and counter threats and keep Canada safe here at home."

Harper said it would become clear in days to come whether the man who launched a gun attack on parliament - and whom he called "a terrorist" - was acting alone or had accomplices. A Canadian soldier was shot dead near parliament at the National War Memorial on Wednesday.

"This week's incidents are a grim reminder that Canada is not immune to the types of terror attacks we have seen elsewhere around the world," he said.

"Attacks on our security personnel and on our institutions of government are by their very nature attacks on our country, on our values, on our society and on us Canadians."

On Monday, a Muslim convert ran over two Canadian soldiers with his car in a Quebec parking lot, killing one. That attacker, 25-year-old Martin Rouleau, was among 90 people being tracked by the Royal Canadian Mounted Police on suspicion of taking part in militant activities abroad or planning to do so. Rouleau was shot dead by police after a car chase.

It was not known whether the gun man in Wednesday's incident was among those 90 people.