The Alberta Children’s Hospital went on lockdown after police received a false report of firearms in the building, on the same night two other Canadian hospitals were also threatened with similar calls.

Calgary police were called to the hospital at approximately 8:40 p.m. on Sunday after someone called 911 claiming they and others had firearms and were entering the building.

The hospital was immediately put on lockdown and several nearby roads were closed off for nearly an hour as emergency crews searched the area. Police didn’t find any threat and the lockdown was lifted at around 10 p.m.

Police described the incident as a case of “swatting” – when someone misleads emergency services into dispatching personnel for a false alarm.

In Toronto, the Hospital for Sick Children, also known as SickKids, went on lockdown for several hours on Sunday evening after police received a call about a threat to public safety. Officers conducted a sweep of the facility and surrounding area and didn’t find anything of concern.

Around the same time, Edmonton’s Stollery Hospital received a similar call about a potential firearms threat. Police conducted a search, which didn’t turn up anything. The hospital wasn’t put on lockdown.

Duty Insp. Paul Wozney for the Calgary police told reporters that they believe the three incidents are connected.

“You look at the timing of it, right? Three children’s hospitals that were called in one evening, that in itself is certainly a very unique set of circumstances,” he said during a press conference on Monday. “There’s also parts of the investigation that we’re not willing to disclose to the community right now that also lead us to believe that it’s connected to one another.”

Calgary police said they have noticed an increase in swatting calls lately.

“Swatting calls have the potential to create significant risks to both public and officer’s safety and can require an extensive amount of resources to respond and investigate,” Wozney said.

“It affects our response, there’s a trickle-down effect,” he said.

Police are continuing to investigate the incident, but no arrests have been made so far.

With a report from CTV Calgary’ Kevin Fleming