Stephen Harper is vowing a speedy passage of legislation that would boost the powers of Canada's spy agency and police forces after a gunman's attack in Ottawa.

"Our laws and police powers need to be strengthened in the area of surveillance, detention and arrest," the Prime Minister told the House of Commons. "They need to be much strengthened. I assure members that work which is already under way will be expedited."

Mr. Harper and other party leaders took to the floor of the Commons on Thursday in a display of unity in which all said Canadians will not be intimidated by the violence that had visited the seat of government. The Prime Minister publicly embraced both Official Opposition Leader Thomas Mulcair and then Liberal Leader Justin Trudeau, a signal of common purpose just metres from where an assailant was shot dead by Parliamentary Hill security one day earlier.

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But while the Conservative Prime Minister and his rivals talked of standing together, Mr. Harper's characterization of and response to what happened in Ottawa differed noticeably from those of opposition rivals, who pleaded for MPs not to let the attack change Canada and the liberties citizens enjoy.

Mr. Harper used "terrorism" or "terrorist" five times in his address, calling the assault on the War Memorial and Parliament a "terrorist attack," and saying there are increasing numbers of places "where the planet is descending into savagery" as he emphasized the need to give security and police forces new powers.

"Make no mistake, even as the brave men and women of our Armed Forces are taking this fight to the terrorists on their own territory, we are equally resolved to fight it here," the Prime Minister said, referring to the Canadian fighter jets and surveillance planes recently deployed to a combat mission in Iraq.

Mr. Trudeau, however, described the Ottawa gunman as a criminal whose actions should not be allowed to redefine the rule of law in Canada. "Criminals do not dictate how we act as a nation, how we govern or the way we treat each other," he told the Commons. "They do not dictate our values. They will not make the rules about this land we share."

Mr. Mulcair urged MPs not to "allow hatred and violence to change our identity." The NDP chief said that on Wednesday, "We woke up in a country of love, diversity, peace, and this has not changed," he said. "We cannot allow that openness and freedom to be rolled back," he said of Parliament.

The contrasts foreshadow a debate that will soon take place in the Commons about how Canada should rewrite laws to deal with the threat of jihadi extremists. The country has proven adept at stopping radicalized citizens from going abroad by cancelling their passports, but not so proficient at preventing them from turning on their own citizens.

Justice Minister Peter MacKay told reporters the government is trying to find the right balance between civil liberties and protecting national security.

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"We're examining all of those sections of the Criminal Code and all measures under the law that will allow us to, in some instances, take pre-emptive measures," he said.

Police themselves are asking for more powers.

Ottawa police chief Charles Bordeleau said on Thursday that authorities need additional tools to catch extremists.

"I think we're seeing a gap evolve in law enforcement's ability to maintain control over these individuals that are being radicalized."

The NDP said it is willing to co-operate with the government to move legislation through, but that does not mean it will support anything the Tories want.

NDP public safety critic Randall Garrison said MPs need full reports on the two killings of soldiers this week to determine whether changes the Conservatives are planning would have helped.