TORONTO -- A 22-year-old man is in critical condition after he jumped onto the back of a truck, fell off and hit his head in East York overnight Saturday.

Toronto police said the incident happened near O’Connor Drive and Donlands Avenue at around 2:15 a.m.

The man was with his friends outside a local business, police said. He then allegedly left the group and jumped onto the rear bumper of the white cube van when it stopped at a red light, police said.

Investigators said the light turned green and the truck turned left, which resulted in the man falling off and sustaining life-threatening injuries.

Police said they found the man unconscious on a roadway, and he was taken to hospital by paramedics.

COLLISION:

O'Connor Dr + Donlands Av

**2:16 am**

- Man jumped onto the back of a moving truck

- Fell off + struck his head

- Found unconscious

- Officers assisting EMS with emergency run

- Man in critical condition

- Officers looking for driver + white cube van#GO2497348

^dh — Toronto Police Operations (@TPSOperations) December 28, 2019

The driver of the white cube van, who has not been identified, kept going and left the scene without speaking to police.

In a message posted to Twitter Saturday morning, police said that investigators believe the driver may not be aware of what happened.

“The driver of the van may not have known the man was on the back of the van but we would still like to speak with him,” police said.

The intersection was closed for an extended period while police investigated at the scene. It reopened shortly after 8 a.m.

Anyone with information or dash camera footage is asked to contact police.