Five males including three children were killed last night in Leeds when a stolen car collided with a tree.
Police were called to the incident in the city at 9.54pm where the Renault Clio crashed.
A 12-year-old, two 15-year-olds, a 24-year-old and a 28-year-old died in the smash, West Yorkshire Police said, while two 15-year-olds are in police custody.
The families of the deceased have all been informed, investigators said.
The road remains closed while the major collision enquiry team investigates the cause of the accident.
A spokesman for West Yorkshire Police said officers were confronted by a scene of "complete carnage" when they arrived at the crash site.
He said that just one vehicle had been involved but it was not yet clear whether the five victims and two suspects had all been in the car.
"Whether they were all in the car or whether some of [the victims] were pedestrians we can’t say at this point in time.
"We’ve got the road closed, an investigation in place and we’re trying to find out what’s occurred."