One of Quebec's most historic buildings was caught up in a massive fire and collapsed late Friday. No injuries were reported, police said.

Witnesses said there was a fire followed by an explosion at the Quebec City Armory, which was built in 1884 and houses the Voltigeurs, a Canadian Forces reserve unit and the oldest French infantry regiment in the country.

The fire was still raging as of about 1:30 a.m. Saturday, said Capt. Paul Sacca, a spokesman with the Canadian military who was at the scene. He said no one was inside the building when the fire started.

Most of the building collapsed about two hours after the fire began, leaving only a brick wall and two towers standing at the main entrance.

Police say they do not know what caused the blaze, and Sacca said they did not suspect terrorism. At least eight fire trucks and dozens of firefighters were at the scene.

The building, which was being renovated, also contained a museum. It is famous for its suspended wood ceiling, the largest in Canada.

"The fire started there so imagine the result," Sacca said. "The roof fell and it was very dangerous for firemen to work in those conditions so they had to work for a long time outside of the building. They've only entered a few minutes ago."

The building had been scheduled to host events for Quebec City's 400th anniversary this year.

"It is one of the most beautiful buildings in Quebec City," Sacca said.