Montreal authorities say a fire at a popular nightclub in the city's Gay Village was deliberately set.

Pointing to accelerants found in the debris, police confirmed that the Tuesday morning fire at Stereo on Ste-Catherine Street was deliberately started.

It's the second time in 14 months that the club has been targeted by arson. A major fire at the after-hours establishment in July 2008 gutted the building, forcing the owners to close for a year for major repairs.

The club was set to re-open this weekend with a splashy five-day party starting Thursday night, but owners said that will probably be delayed.

Co-owner Tommy Piscardeli said he's not sure who is behind the arson, but he is frustrated his business was targeted again.

"I really don't know what it is," he told CBC News. "It could be anything, but I just want it to stop. We want to give people some music, we want to give people a good place to be, and we're having a really hard time doing it."

Hundreds of people have already bought tickets for the re-opening party, including Hector Breault, who is disappointed the event probably will be delayed.

"We love Stereo," he said. "I hope it's going to reopen, I hope."

A security guard discovered the fire early Tuesday morning, police said.

Arson investigators are still at the three-floor building collecting evidence.