An armed man is believed to be holding hostages in the Workers' Compensation Board building in downtown Edmonton, police say.
A board spokesman confirmed the hostage taker is a disgruntled workers' compensation claimant.
An employee who was evacuated from the third floor of the building told CBC News reporter Trish Estabrooks that as many as nine hostages were being held on the eighth floor.
"At 8:42 this morning, we received a call that a man with a rifle had walked into the Worker's Compensation [building]," said Edmonton police spokesman Jeff Wuite.
"We, of course, responded immediately. Our officers are currently speaking with the man who is inside. We do believe he may have several hostages.
"We have tactical officers on scene, as well as our negotiation team and they [will] attempt to bring this to a peaceful conclusion," Wuite said.
One employee who got out of the building told CBC News reporter David Gerow that a tall bald man entered the building with a gun, and one shot was fired, but no one was injured.
Wuite said he did not have a firm idea of the number of hostages. Nor would he confirm reports that a shot was fired.
About 700 people work in the building, and many of them streamed out to call friends and relatives to tell them they were OK.
When asked if the gunman had a grievance, Wuite said, "At this point, we're still trying to determine any motives behind this situation."