An unknown number of vehicles were involved in a massive pileup on Highway 401 near Newcastle Friday afternoon.

It happened at around 3:30 p.m. in the westbound lanes of Highway 401 near Newtonville Road.

To see images from the crash, click here.

The crash forced the closure of all eastbound and westbound lanes of the highway between Highway 115/35 and Newtonville Road for several hours.

The eastbound lanes were reopened at around 10:30 p.m.

Snow is believed to have been a factor in the collision.

"At this point it is just too early to know exactly how many vehicles are involved," Const. Linda Wolf told CP24 Friday afternoon. "We are dealing with the injuries first and counting of the cars will come later."

According to Durham EMS, seven people were taken to hospital, including two with life-threatening injuries.

At one point a total of 12 ambulances from Kawartha Lakes, Durham Region and Peterborough and Northumberland counties were on scene.

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