LONDON, Ont. - Ontario's police watchdog says it's investigating an incident in London, Ont., where a man set himself on fire during a confrontation with police early Friday afternoon.

The Special Investigations Unit says officers responded to a 911 call about a man in distress outside the Immigration, Refugees and Citizenship Canada office on Exeter Road around 1 p.m.

The SIU says the officers tried to talk to the man, who was threatening to harm himself.

The agency says the situation escalated and the man set himself on fire after the officers fired plastic projectiles from an anti-riot weapon in an attempt to subdue him.

Firefighters, who were already on scene, quickly extinguished the fire and the 48-year-old man was taken to hospital for treatment of serious injuries.

The SIU is an arm's length agency that investigates reports involving police where there has been death, serious injury or allegations of sexual assault.