One person has died and two others were injured following a crash on Highway 401 in Ajax.

According to police, a tractor-trailer and a car collided in the eastbound lanes of the highway near Lake Ridge Road at around 5 a.m.

A 20-year-old male victim, who was ejected from the car, was without vital signs when he was transported to a local hospital in Ajax. He was pronounced dead a short time later.

A second victim was taken to St. Michael's Hospital in Toronto with critical injuries and a third victim suffered minor head injuries.

All three victims were occupants of the car.

The driver of the truck was not injured, police confirmed.

It is not clear what caused the collision but police say charges could be laid.

All eastbound lanes of the highway were closed at Salem Road for several hours but have since reopened.

The OPP collision reconstruction unit is on scene and police have not said when the highway is expected to fully reopen.