Emergency services are at the scene of a serious crash on the M5 in South Gloucestershire.
We were called at just after 2.30pm to the collision between J14 and J15 involving several vehicles including a lorry.
Local police said it would be shut "for a considerable amount of time".
Expressways England cautioned of "long postponements" and prior said there was a six-mile line northbound between intersection 18 for Avonmouth and 16 for Almondsbury.
"Sadly, at least four people have died", Avon and Somerset Police said in a statement.
It is the second fatal crash on the same stretch of the M5 this week. "One vehicle was completely destroyed, nearly like there was only half a auto left with what looked like somebody trapped inside".
Witnesses reported seeing people lying by the side of the road as members of the public helped pull survivors from wrecked cars, with some performing first aid.
He said drivers who had been stuck on the carriageway for a few hours were in effect "extremely supportive".
South Western Ambulance Service Trust said a dozen ambulances and a critical care team were working at the scene.
Another person wrote the lorry had crashed through the central reservation and drove off the road.
Avon Fire & Rescue Service sent six appliances and its Major Rescue Tender to the scene.
It added drivers on the M4 planning to join the M5 northbound were unable to do so.