B.C.'s police watchdog is investigating after an RCMP officer drove into a pedestrian in Squamish late Tuesday night, leaving the man in critical condition.

The Independent Investigations Office said the crash happened at the intersection of Highway 99 and Garibaldi Way at around 10:30 p.m.

The officer, who was on duty but wasn't responding to a call, was driving an unmarked SUV at the time.

According to the RCMP, the Mountie called in the accident and tried to provide medical assistance to the victim, who is in his late 20s.

The pedestrian was taken to hospital, where he remains in critical condition.

Few other details have been confirmed, including whether the man was crossing the street with the right-of-way when he was struck.

Southbound traffic on the highway was rerouted for several hours Tuesday morning while investigators from the Integrated Collision and Reconstruction Service gathered evidence, but has since reopened.

Anyone who might have witnessed the accident is asked to contact the IIO at 1-855-446-8477.