The Special Investigations Unit in Ontario was called following a fatal collision on Highway 401 in Whitby on Monday evening, police said.

The Durham Regional Police Service (DRPS) stated that at around 7:50 PM, they were called to a robbery near Green Road and Highway 2 in Clarington.

DRPS wrote in a statement provided to CP24: "The suspect fled in a car that police were pursuing. During the chase, the suspect's vehicle entered 401 heading in the wrong direction."

A collision involving several vehicles occurred, resulting in fatalities.

The number of people injured or killed in the collision that took place east of the Highway 412 interchange is currently unknown. However, several emergency vehicles can be seen in MTO camera footage from the scene.

The number of vehicles involved in the collision that occurred in the eastbound lanes of Highway 401 is also unclear.

As a result of the accident, Highway 401 is closed in both directions from exit 406 (Lake Ridge Road / County Road 23) to exit 410 (Brock Street / County Road 46).

The ramp from Highway 412 southbound to 401 eastbound is also blocked at this time due to the collision.

In a video posted on social media, Sergeant Kerry Schmidt of the OPP said he expects significant delays with the closures and urged motorists to use Victoria Street to the south and Highway 2 to the north as alternate routes.

He said, "I expect the reconstruction of the collision to take most of the night and possibly into the morning rush hour as well."

"Expect delays. Expect congestion in the area." Collision: #Hwy401 is closed in both directions between Lake Ridge Road and Brock Street in Whitby.