One woman has died in a collision between a lorry and a minibus on its way to a hen party on the M62 in West Yorkshire.
A lorry driver has been arrested after the motorway pileup that left 19 people injured including six who were seriously hurt.
The collision happened on the westbound carriageway of the M62 near Pontefract at around 11.30am.
Rescuers are working to free those who remain trapped, West Yorkshire Police said.
The minibus was believed to be carrying a group of around 20 women, all from the West Yorkshire area, police said.
The women were on their way to a hen party
Emergency services - including six air ambulances - were called at 11.30am to junction 32 of the M62 after the crash near the Xscape leisure park.
Police said the incident had left the motorway closed in both directions and advised motorists to avoid the area.
19 people were injured in the crash
A spokesman said the driver of the lorry, a local man, has been arrested in connection with the incident.
Assistant Chief Constable Craig Guildford, of West Yorkshire Police, said: "This is a significant incident with a number
of casualties and as a result of this we have had to close the motorway to allow emergency services to safely get to and free those who are injured.
"We realise this will cause disruption and I would ask drivers to bear with us and avoid the motorway in that area as there will be significant delays."
"Emergency Services remain on the scene and will re-open lanes of the M62 in the area as soon as we can do so safely, but clearly the priority at this stage has been recovering those who are injured.
Six air ambulances were used in the rescue operation
"Anyone who is concerned about a family member or who has witnessed the collision itself is asked to contact West Yorkshire Police on 101 for information."
A spokeswoman for the Yorkshire Ambulance Service NHS Trust said: "We received an emergency call at 11.31am today to reports of a serious collision between a mini-coach and an HGV at junction 32 of the M62, close to Castleford, West Yorkshire.
"Due to the scale of the incident we have enacted our major incident plan and dispatched a number of resources to the scene including ambulances, our hazardous area response team, doctors and air ambulance.
"Ambulance clinicians are providing treatment at the scene and are working closely with their emergency service colleagues.
"At this time the number of patients is unknown."
Kevin Hodgson, director of operations at Great North Air Ambulance, said they had sent two air ambulances, which
were joined by two from North West Air Ambulance and another two from Lincolnshire and Nottinghamshire Air Ambulance.
He said one had taken a casualty to Leeds General Infirmary while another was en route to the James Cook University Hospital in Middlesbrough with a patient on board.
The M62 was closed after the crash
"We do not know the exact state of the injuries, but certainly the patient en route to the James Cook Hospital was anaesthetised on scene by the doctor and paramedic," he said.