Fourteen people have been injured, some seriously, after a crash involving two cars in Stevenage.
Hertfordshire Constabulary said the cars were involved in a collision on Monkswood Way at about 9.45pm on Thursday.
Reports on social media suggest the incident happened during a car meet event and that a group of people standing at the side of the road were hit.
A police spokeswoman said: “There were a number of people in the area at the time and 14 people are presently being treated for injuries, some of which are serious.”
The East of England Ambulance Service said it had taken 12 people to three hospitals – Lister Hospital in Stevenage, Watford General Hospital and The Princess Alexandra Hospital in Harlow.
An air ambulance also attended the incident.
Footage posted on Twitter shows a car passing another vehicle before the two collide and plough into crowds.
One witness said on Twitter: “I’ve just witnessed that horrendous crash in #Stevenage, no more than 50ft away from me. I’m still trying to process it all.”
A group called Cruise-Herts had said on Facebook that it was holding a car meet event on Thursday to raise money for a charity supporting bereaved parents.
Rix Sidhu, of the club, told the MailOnline: “We organise static meet-ups. We park up and walk about and admire the cars, we’ve even had families come in the past.
“We’ve been doing this for 10 years.
“But we can’t control everyone and we don’t promote this. We are not boy racers, we are car enthusiasts.”
Emergency services are expected to remain at the scene for some time.
Police have urged any witnesses to get in touch and have asked anyone with footage of the incident to email it to OPtephra@herts.pnn.police.uk.