A pedestrian was seriously injured after a police car ploughed into a wall.
Emergency services rushed to the scene Brighton, East Sussex, after the smash.
Photos show multiple ambulances and police cars on the road in the Elm Grove area of the town.
Witnesses heard screams at around 7.30am.
Sussex Police confirmed it is at the scene.
One resident posted on Twitter: "Apparently a police car crashed into a wall and it collapsed, someone airlifted to hospital."
Speaking from their home, another resident said: “We heard a scream but we didn’t hear a crash. We saw someone taken into an ambulance - they didn’t look like a police officer though.”
Another witness told Brighton Argus: "I was in my garden and I heard all these sirens.
“I went to take out my recycling and the whole street was full with cars.
“It looks like it happened just opposite the nursery.”
A spokesman for the police force said: "A Sussex Police car, which was responding to an emergency incident, has been involved in a road traffic collision with a pedestrian in Bear Road, Brighton, around 7.40am on Wednesday.
"The pedestrian suffered serious leg injuries and has been taken to the Royal Sussex County Hospital. Two police officers suffered injuries, not believed to be serious.
"The road is currently closed and the matter has been referred to the Independent Office for Police Conduct, as in routine in these circumstances."
