Prime Minister Stephen Harper says the federal government will do "everything possible" to help rebuild Quebec City's armoury, which was destroyed in a weekend fire.

In question period Monday, Harper called the military drill hall "one of the most important historic buildings" in the provincial capital, and said the Conservative government would assist in reconstruction efforts of facilities that "illustrate so well the military history of the city."

Liberal Leader Stéphane Dion pressed for a firm commitment from Harper and Canadian Heritage Minister Josée Verner, who represents the Louis—St-Laurent riding, in the Capitale-Nationale region.

"Will it be rebuilt as quickly as possible, yes or no?" Dion asked.

The federal government indicated earlier the armoury's destruction was a "priority."

The comments came as Quebec City Mayor Régis Labeaume appealed to the federal government for assistance to reconstruct the historic armoury, which burned down Friday night.

Labeaume has already sent a written request to Harper for financial help to rebuild the landmark armoury drill hall that was home to Canada's oldest French regiment, les Voltigeurs.

Quebecers are keen to get on with building a new armoury, especially because of the building's role in upcoming celebrations of the capital city's 400th anniversary, Labeaume said.

Several anniversary events, including a military music festival, were planned at the armoury.

Organizers hope the ruins can be salvaged to allow activities on the front lawn.

Military police seek eyewitnesses

Canadian military police investigating the fire admit their work is difficult because of extensive damage to the building, which is in a "pitiable state," said Lt. Marie-France Poulin.

"There was huge damage and we're still looking for the originating point of the fire," she told Radio-Canada on Monday.

Police are asking people with photos or videos of the fire to submit them to authorities. 

No arms or explosives were stored in the building, police said.

History goes up in smoke 

Most of the armoury building was destroyed, including its wooden ceiling, the oldest of its kind in North America.

But firefighters and soldiers salvaged about 90 per cent of objects stored in the building, including the Voltigeurs Regiment's official flag and military documents, said Raymond Falardeau, a curator at the Musée du Manège militaire de Québec.

The building was designed by architect Eugène-Étienne Taché in the 19th century and opened in 1887. It's considered to be the second most important military building in Quebec, after the Citadelle, also in Quebec City.

The armoury belongs to the Ministry of National Defence.