Image copyright Newsimage Image caption The incident took place at around 3am on Friday
A man has been arrested after a crash on the A23 that killed two people and closed the road for hours.
A second woman was critically injured in the incident in Surrey, police said. The cars involved were described as a Ford Mondeo and a van.
One witness said he heard screams as the cars burst into flames and believed they were caused by fireworks being discharged by a group of men.
Video footage on social media shows flames coming from a vehicle on the side of the road.
A man, in his 50s, was arrested on suspicion of causing death by dangerous driving and bailed until Thursday 9 April.
Road closures in the area in Berkshire resulted in tailbacks for miles as rush-hour traffic waited at the side of the road.
Detective Inspector Chris Enck said: “We believe the crash is not suspicious but are yet to establish the cause.
“Initial inquiries indicate no-one else was involved.
“The road is likely to remain closed for some time but I would urge those who are close to the scene to avoid it.”
Image copyright Newsimage Image caption Police took to Twitter to ask members of the public for information
Image copyright Newsimage Image caption Smoke billowed from the accident site