Canadians gathered for a sombre anniversary on Parliament Hill on Thursday to remember two soldiers who died on home soil last October in separate attacks that sent shockwaves through the country.

Gov. Gen David Johnston said Canadians continue to mourn the deaths of Cpl. Nathan Cirillo and Warrant Officer Patrice Vincent.

"It's been one year. We continue to grieve. We continue to heal," Johnston said during a ceremony at Ottawa’s National War Memorial.

Cirillo was shot and killed on Oct. 22, 2014 while standing ceremonial guard at the Tomb of the Unknown Solider. The gunman then stormed Parliament Hill's Centre Block firing dozens of shots before he was shot dead.

The attack came two days after Martin Couture-Rouleau drove his car into two soldiers in Saint-Jean-sur-Richelieu, Que., killing Vincent. Police said Couture-Rouleau was a radicalized Quebec man who had been on the RCMP's radar.

"Last October, many people said Canada would never be the same," Johnston said. "But I don’t think Canada changed forever. Canadians are a caring, and a courageous people. This is who we are and that will not change."

Thursday's ceremony drew a large crowd to Parliament Hill, which included the families of Cirillo and Vincent, prime minister-designate Justin Trudeau and outgoing Prime Minister Stephen Harper.

Harper and Trudeau participated in a wreath-laying ceremony together, along with Johnston, Ottawa Mayor Jim Watson and Chief of Defence Staff Gen. Jonathan Vance.

The ceremony included a 21-gun salute, two minutes of silence and a flypast by four CF-18 fighter jets.

Harper said in a statement that Thursday was a day to pay tribute to all the first responders who risked their safety to stop the brazen attack.

“It was inspiring to see how Canadians came together in the aftermath of these attacks, offering each other support, condemning terrorism, and showing the courage and resolve that make our country great,” he said.

Trudeau said Canadians will continue to help and protect each other, pointing to Canada's veterans and military personnel.

“We will not allow threats to shape us, nor bow to those who mean to undermine our values and way of life," he said in a statement. "Canadians are kind and generous, open-minded, and optimistic."

Attack had 'profound' impact on Canada

Johnston said earlier on Thursday that the attack had a "profound" impact on Canada, "where we have so much freedom."

"What we're recognizing today is that our liberties are very precious ones," Johnston told CTV News Channel ahead of the ceremony. "We should never allow them to be clouded in any way, but to reinforce them whenever we can."

RCMP Assistant Commissioner Gilles Michaud said in a statement that the agency continues to work hard to ensure such a tragedy does not happen again.

"We will never forget what happened on October 22, 2014, but we are resilient and will continue to pursue and prevent threats to our safety," Gilles said in a statement.

In the aftermath of the shooting, RCMP worked collaboratively to create the Parliamentary Protective Service which ensures "better information and intelligence sharing" and "more consistent training."

Michaud said officials are working on two studies looking at ways to make Parliament Hill more secure, which could lead to highly visible security measures.

Kevin Vickers, Canada's former Sergeant-at-Arms who was credited for his role in stopping the shooter, said Thursday that his thoughts are with the victims' families and the first responders.

On Wednesday, mourners gathered for a sunset ceremony in Cirillo's hometown of Hamilton, Ont. to remember the 24-year-old reservist.

"It was cowardly, it was evil, and most of all, it was tragic," Cirillo's sister Nicole told the crowd.

Cirillo, a member of the Argyll and Sutherland Highlanders regiment, left a young son, Marcus, who attended the ceremony with his mother along with other family members.

"May his life and death inspire all of us to work for greater peace in our nation and in our world," regimental chaplain Robert Fead said during the ceremony.

Michael Zehaf-Bibeau, who shot Cirillo, recorded a video message before the Parliament Hill attack, in which he said his actions were "in retaliation for Afghanistan" and other Canadian military missions.

With files from The Canadian Press