The threat of terrorism is still prevalent nine years after the airborne attacks of Sept. 11, 2001 - even in Canada, Prime Minister Stephen Harper warned Saturday.
In a statement marking the anniversary of the U.S. attacks, Mr. Harper said no country is immune to terrorism.
"Sadly, the threat of terrorism is still very much a global reality, including right here at home," Mr. Harper said. "No country is immune.
"International and home-grown radical groups continue to pose a real danger to our safety, and we must remain ever-vigilant."
Twenty-four Canadians were among 2,974 people killed when terrorists hijacked four passenger planes, crashing two into New York's World Trade Centre and one into the Pentagon in Washington.
Another plane, believed destined for the U.S. capital, crashed in a Pennsylvania field after passengers tried to overpower the hijackers.
They were seminal events, forever changing the western world's perception of its own safety and security. Canada has been part of the so-called war on terrorism ever since, losing 152 soldiers and four civilians in Afghanistan since it joined the fight there in 2002.
In a joint statement, Foreign Affairs Minister Lawrence Cannon and Public Safety Minister Vic Toews reiterated the country's support for that fight, despite plans to have all Canadian combat troops out of Afghanistan by next summer.
"These were cowardly attacks on our freedom and on our values," said their statement. "Canada stands side by side with the United States in the battle against terrorism and extremism worldwide.
"We stand for the protection of our citizens, our fundamental freedoms and the building of a secure future for our children.
"Canada has always stood for the values of freedom, democracy, human rights and the rule of law."
Mr. Harper said his Conservative government has been taking "decisive action" since the hijackings to stop terrorist financing, terrorist operations and terrorist attacks.
"The tragic events of Sept. 11 remain fresh and clear in all of our hearts and minds," he said. "The memory of that day continues to evoke horror and sorrow in all Canadians, despite the passing of nearly a decade.
"Today, as we honour the victims of 9/11 and their loved ones who still grieve, we also honour the brave men and women who put their lives on the line every day to help prevent such a terrible tragedy from happening again."
Last month, three Ontario residents were arrested after investigators uncovered what reportedly was a plot to bomb specific government buildings and public transit systems.
Police seized terrorist literature, videos and manuals along with more than 50 electronic circuit boards they say were designed specifically to remotely detonate homemade bombs
Misbahuddin Ahmed, 26, and Hiva Alizadeh, 30, both of Ottawa, and Khurram Sher, 28, of London, Ont., are behind bars awaiting trial on conspiracy- and terrorism-related charges.
Police say others were involved and the plot reached far beyond Canada's borders to Iran, Afghanistan, Pakistan and Dubai.