A naked swimming event planned for the Southland Leisure Centre in Calgary will not be allowed on Sunday due to security concerns.

James McLaughlin, acting director of recreation services, made the announcement Thursday morning, saying public commentary on the planned event became too volatile to ensure the safety of all users.

"I can't say there was any one specific threat, there was a series of different things that occurred over time relating to the ongoing public discourse," he said.

"[The decision] is not in response to the public backlash, it's in response to specific commentary that was made in some of the threads within the discussions that were ongoing."

Police said in a statement that on Monday they received a report of a threat to the leisure centre in relation to the naturist event.

Officers responded, but determined that there was no immediate danger. Police said the incident is still under investigation.

The group wanting to host the event, Calgary Nude Recreation, posted a statement to social media soon after the decision was announced.

"It is outrageous that lawful recreation can be prohibited by an incredibly vocal minority," it read. "These people must NOT be allowed to dictate public policy with threats against law-abiding citizens engaged in lawful activities."

The group said it will continue to book events in Calgary and will pursue legal action to ensure those are allowed to go ahead.

The group said it will also begin working toward establishing "a legal, clothing optional stretch of river within reasonable distance of the city core for people to participate in legal recreation."

Ugh. I hate when I'm reminded that this city contains so many narrow-minded rednecks. <a href="https://twitter.com/hashtag/berta?src=hash&ref_src=twsrc%5Etfw">#berta</a> —@MacgowanC

McLaughlin noted nude swimming events have been hosted at city facilities for several years.

A petition calling on the city to cancel the event or make it adults only had gathered more than 20,000 signatures by Thursday morning.

A petition against that petition got nearly 6,000 signatures.

The leisure centre's Facebook page was flooded with vitriolic comments and one-star reviews regarding the naturist event.

"Hopefully, people like this will be invited to enter the ovens," wrote one commenter.

"I'll never set foot in Southland Leisure Centre with my family after hearing about your pedophile soup event," wrote another.

Other events are also planned for Southland Leisure Centre on Sunday evening, said McLaughlin.

"The challenge is that it's a large facility, so while this group has done a private booking for the aquatics components, we have another private booking in the gymnasium, the arenas are open to the public or are in continual use the whole time period as well," he said.

"It's not just this one group, it's everybody that's going to be coming to the building who will be impacted."

McLaughlin said the city receives upward of 16,000 bookings per year at its facilities.

"Each and every booking is a unique activity, some are private, some are through existing social organizations [and] sporting groups," he said.