A ceremonial service to commemorate the Parliament Hill shooting and the lives of two soldiers killed on their home soil last October is set to take place at the National War Memorial this morning.

Outgoing Prime Minister Stephen Harper, prime minister-designate Justin Trudeau, Gov. Gen. David Johnston and Ottawa Mayor Jim Watson, as well as members of the public and military, will gather around the granite arch of the memorial to pay tribute.

Pat McDonnell, the interim sergeant-at-arms, and the RCMP's Michael Duheme, head of the newly created Parliamentary Protective Service, will also attend.

The ceremony will take place one year to the day after Cpl. Nathan Cirillo, 24, was shot in the back three times while standing guard at the memorial, the first event in a five-minute attack during which the shooter stormed Parliament Hill's Centre Block.

The ceremony will also commemorate Warrant Officer Patrice Vincent, a 53-year-old Canadian Forces member who was purposefully run down in a hit-and-run attack in Saint-Jean-sur-Richelieu, Que., just two days before Cirillo was slain.

The families of the two soldiers are expected to attend the ceremony and Harper is expected to lay a wreath at the memorial.

The ceremony will include the flyby of CF-18 Hornets in "missing man" formation at 11:20 a.m., a 21-gun salute by the 30th Field Artillery Regiment and a speech by Gov. Gen. David Johnston.

A 200-person marching contingent of soldiers and a Canadian Armed Forces band will also take part in the ceremony.

Later Thursday, at 1 p.m., the Parliamentary Protective Service will hold a private ceremony in the House of Commons. Samearn Son, a guard who was shot in the leg as he struggled with the gunman, is expected to attend. He continues to work on Parliament Hill.

Soldiers killed by men with extremist views

Cirillo and Vincent were both victims of men who held extremist views.

Michael Zehaf-Bibeau, who shot Cirillo, was himself shot to death inside Centre Block. Minutes before the shooting he recorded a video message on a cellphone, saying his actions were retaliation against Canadian military missions in Afghanistan and Iraq.

Martin Couture-Rouleau, who drove his car into two soldiers and killed Vincent, was shot to death by police two days later.

Couture-Rouleau was a Muslim convert who made increasingly radical statements on social media and was on an RCMP watch list.