The province's police watchdog is investigating a Thursday morning shooting involving a Toronto police officer.

The Special Investigations Unit (SIU) said police received a 911 call about an assault near Cobbler Crescent and Driftwood Avenue, close to York University, shortly after 9 a.m. When officers arrived on the scene, they found a 26-year-old man stabbing another man.

SIU spokesperson Jason Gennaro said there was an "interaction" and a police officer fired, striking the alleged assailant.

The man who was stabbed is believed to be around 60 years old. Paramedics rushed both men to hospital and they are now in non-life-threatening condition.

SIU Jane Driftwood shooting

The province's police watchdog is investigating a shooting involving a police officer. (Mehrdad Nazarahari/CBC)

Gennaro said it's unclear whether or not the men knew each other. He would not confirm the number of shots fired by police.

No officers were injured.

'Everybody was screaming'

Chris Precius watched everything unfold from his balcony. He told reporters Thursday he woke up to sounds of a fight, then saw the alleged assailant punching the other man for three or four minutes before police arrived.

Chris Precius

Chris Precius saw the shooting from his balcony. (Mehrdad Nazarahari/CBC)

The man receiving the blows didn't fight back.

"Everybody was screaming, everybody was running," Precius said. "Everybody was trying to get the guy's attention, but he wasn't listening."

The shooting happened soon after police arrived on the scene, Precius said.

"I heard [the officer] say, 'Hey! Stop!' And then he popped one into the guy."

"It wasn't two seconds, three seconds," Precius said.

Gennaro said there was a TTC bus at the scene and investigators will be looking into whether the vehicle captured the shooting on its surveillance cameras.

The SIU is automatically called in to investigate reports of death, serious injury or allegations of sexual assault involving police.