Several dead in 50-vehicle Pennsylvania pile-up

A number of people have died in a motorway pile-up involving more than 50 vehicles in Pennsylvania, authorities say.

The crash, 120km (75miles) north-west of Philadelphia, left trucks and cars strewn across three lanes of traffic and the central reservation.

The Pennsylvania Emergency Management Agency said 40 people had been taken to hospital and 70 to a temporary shelter.

Drivers have been urged to use caution amid cold weather and drifting snow.

A spokeswoman for Penn State Hershey Medical Center said three patients had been brought in in a critical condition, three more with moderate to severe injuries and four with minor injuries.

Agency spokesman Cory Angell said drifting snow had been reported in the area of the crash, which took place on the eastern carriageway of Interstate 78 near the town of Bethel Township.

Officials have warned people in the north-eastern US to stay indoors during what the National Weather Service described as "life-threatening temperatures".