Canada will not be intimidated by terrorism and will enhance its fight against terrorist organizations, Prime Minister Stephen Harper said on Wednesday.

Policemen blank off the street near the Canadian parliament building in Ottawa, Canada, on Oct. 22, 2014.

"We will not be intimidated. Canada will never be intimidated," Harper said in a televised address to the nation after a shooting rampage in the parliament building killed a guard and a gunman.

He added that the security agencies would do everything needed to counter threats to the country.

"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," he said.

Harper's address came as authorities lifted a lockdown in downtown Ottawa, except in the parliament building, after gunshots were fired inside it earlier in the day.

Shootings also reportedly took place at the National War Memorial near the Rideau Center shopping mall.

A soldier standing guard at the memorial was gunned down and later died of wound, while a gunman was killed inside the legislative building, according to Canadian police.

Two days earlier, two Canadian soldiers came under attack in Quebec by a man driving a car. One soldier later died of his injuries.

On Tuesday, Canada raised its domestic terror threat level from low to medium after sending six CF-18 Hornet fighters to the Middle East to join U.S.-led airstrikes on targets of the Islamic State (IS) inside Iraq.

The extremist group has threatened attacks on countries that are participating in the air raids.

In his address, Harper said it would become clear in days to come whether the man who launched Wednesday's gun attack was acting alone or had accomplices.

"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," said the prime minister.

"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," he added.

In Washington, U.S. President Barack Obama said full information was not available yet on the motivation of the "tragic" shootings.

"Obviously the situation there is tragic," Obama told reporters after holding a meeting on Ebola at the White House. "Obviously we're all shaken by it."

He said the shootings emphasized the "degree to which we have to remain vigilant" in dealing with "these kinds of acts of senseless violence or terrorism."

"We don't yet have all the information about whether this was part of a broader network or plan, or whether this was an individual or series of individuals who decided to take these actions," he added.

In his phone talks with Harper earlier, Obama condemned what he called the "outrageous" attacks that occurred in Canada in the past three days and offered "any assistance" needed by Canada in responding to the attacks.

Obama stressed that as neighbors and allies, the United States and Canada have to be "entirely in sync" in dealing with terrorist activities.

In a statement, New Zealand Prime Minister John Key also expressed his sympathies to those affected by the shooting.

"The reasons behind the fatal shooting in Ottawa this morning are not yet known, but it is clearly a senseless act of violence," Key said in the statement.

"I wish to extend New Zealand's sincere condolences to the people of Canada who will be shaken by this violent act. I will personally extend those thoughts and wishes to Prime Minister Harper," he said.

Source: Xinhuanet