Police officers stand outside the apartment where the shooting occurred. (Peter Akman/CBC)

A man shot by Calgary police Tuesday night was living in an apartment building run by an agency that provides affordable housing for people with mental illness and special needs.

Police said officers responded to a disturbance complaint at a downtown apartment complex in the 1100 block of 8th Avenue S.W. at about 9 p.m. MT.

A man armed with a knife left an apartment unit and confronted officers, said acting duty Insp. Frank Farkas.

An officer fired his weapon, and the man was taken to hospital with a single gunshot wound. He remains in serious but stable condition, said ASIRT officials on Wednesday. No police officers were injured.

The name of the man has not been released.

Calgary Police Chief Rick Hanson said his officers acted appropriately based on the information available at the time.

"Somebody being held hostage with a knife at their throat was the preliminary information, so they assess the situation as it unfolds," he said on Wednesday. "So I think we continuously have to be alert as police officers that are out working the street to the potential that it could be a mental illness, it could be drugs, it could be just a violent person."

'He was a threat to the officers, a threat to anyone inside the apartment building, and he was stopped.'—John Dooks, Calgary Police Association

John Dooks, head of the Calgary Police Association which represents officers, said police had little choice with the armed man only about two metres away from them.

"That's what officers have to do, and they do it as quickly and efficiently, with the least amount of force, and sometimes if somebody has a knife and there's no distance between you, firearm is the only choice," he said.

"He was a threat to the officers, a threat to anyone inside the apartment building, and he was stopped."

The Alberta Serious Incident Response Team (ASIRT), which looks into most deaths and serious complaints in the province involving police officers, has been assigned to examine the actions of the officers involved in the incident, officials said.

Building run by non-profit group

The five-storey building, which contains 50 studio suites for people with mental illness transitioning into the community, is owned and operated by the Horizon Housing Society.

"We are fully co-operating with Calgary Police Service as they conduct their investigation," the agency wrote in a media release. "As the property manager, we are not able to comment on any of the specific support programs that are being provided within the building or about the individuals who reside in any one of our properties."

The wounded man's neighbour, Carolynne Gillender, described him as a quiet person who kept to himself.

"No issues at all, whatsoever," she said. "You never heard anything come out that he was violent or anything like that .… It shakes up the whole, building, the whole community that lives here."

Lisa Stewart, who lives on the building's second floor, heard gunfire.

"It was loud. It was very loud. It sounded like it was right above me," she said. "This is the first time I've heard a gunshot in my building. It is very scary. I've been here four years."

It is the second time in less than a week that a man was shot by city police.

On Sunday, Calgary police shot and killed a man carrying a sawed-off shotgun after a two-hour standoff in which he was holding a 19-year-old neighbour hostage in the southwest community of Southwood.

With files from Tara Fedun