Edmonton police say two patrol officers have been killed while responding to a call.
The force did not immediately release details about what happened.
Police Chief Dale McFee and other dignitaries were scheduled to make statements later Thursday.
About a dozen police cars were parked around a northwest Edmonton apartment complex, a large series of brick three-storey walkups. A forensics truck was parked outside one of the buildings.
The scene was taped off and a road leading into the complex was blocked. Police also set up two command posts in the area.
In response to the deaths, the Edmonton Police Commission cancelled a public meeting that had been planned for Thursday.
Police services in Calgary, Vancouver, the Greater Toronto Area and Halifax were among those expressing condolences on Twitter.
"This is a tragic loss and one that is shared among law enforcement including our team. We are here to offer our support to (Edmonton police) as well during a devastating time," Calgary deputy police chief Chad Tawfik wrote on Twitter.
"Condolences to the entire service, families, and friends."
Prime Minister Justin Trudeau also posted a message on Twitter.
"Every day, police officers put themselves in harm’s way to keep people safe," he wrote.
"The news that two Edmonton police officers have been killed in the line of duty reminds us of that reality. I’m sending my condolences to the officers’ loved ones and colleagues – we’re here for you."
Thursday's deaths are the first among the Edmonton Police Service since 2015, when Const. Daniel Woodall, a hate crimes investigator, was using a battering ram to enter a residence when he was shot numerous times through the door. Another officer, Sgt. Jason Harley, was struck by a round that penetrated his body armour and survived.
Before that, Const. Ezio Faraone was shot and killed responding to an armed robbery on June 25, 1990.
This report by The Canadian Press was first published on March 16, 2023.