Six men and two women have died in a crash involving a minibus and two lorries on the M1 near Milton Keynes.
All of those who died were travelling in the minibus, which was from the Nottingham area.
The two lorry drivers have been arrested, one of them on suspicion of driving while over the alcohol limit.
A five-year-old girl, a woman and a man are being treated in hospital with life-threatening injuries, while another woman has serious injuries.
The crash happened on the southbound M1 at Newport Pagnell in Buckinghamshire just before 03:15 BST.
Both men are being questioned on suspicion of causing death by dangerous driving and are in police custody.
The carriageway reopened just after 13:00 BST.
The vehicles were all travelling in the same direction between junctions 15 and 14, police said.
Ch Insp Henry Parsons said some of those involved in the collision were visiting the UK from India.
Buckinghamshire and Milton Keynes Fire and Rescue Service said it had sent six crews as well as three search and rescue vehicles to the scene.
Firefighters used hydraulic equipment to release three people from a vehicle.
Thames Valley Police said the two lorry drivers, one aged 31 and from Worcestershire, the other aged 53 from Stoke-on-Trent, were being questioned.
The 31-year-old man was detained on suspicion of one count of causing death by dangerous driving and one count of driving a motor vehicle when above the legal alcohol limit.
Pictures appear to show extensive damage to the lorries involved – a FedEx vehicle and one belonging to AIM Logistics.
Ismail Elmagdoub, director of AIM Logistics, based in Evesham, Worcestershire, said: “One of our vehicles was involved in a serious incident on the M1 southbound, junction 14 this morning at approximately 3am.
“We would like to express our deepest sympathy to the families who have lost loved ones and also those whom have been injured at this very sad time.
“Road safety and compliance is of the utmost importance to AIM Logistics and we are continuing to assist the police as much as possible with their inquiries.”
The road was closed for several hours while investigation work took place, and Northamptonshire Police asked people travelling to the British Moto GP at Silverstone to allow more time for their journey.
The M1 is expected to be one of the country’s busiest roads over the Bank Holiday weekend.