Six people, including three children, were injured when a car mounted a kerb and ploughed into a crowd of people outside a sports centre in Newcastle.
It happened outside Westgate Sports Centre where an event was taking place to celebrate the end of Ramadan.
One of the children is said to have been critically injured. Northumbria Police said the incident was not believed to be terrorism-related.
A 42-year-old woman was arrested and is in custody, police said.
No-one else was being sought. Extra patrols were in the area to reassure communities, police said.
Hundreds of people were at the event to mark the end of Ramadan.
One eyewitness said: “From what I understand, [a woman who had been at prayer] was about to leave in her car and I believe she lost control.
“I ran up straight away because everyone was moving in on all the injured, trying to put water in their mouths.
“The parents of the kids were there. I had to sort of try and calm them down just to tell them the ambulance is there and they will take care of it; they know what they’re doing.”
A North East Ambulance Service spokesman said: “We have taken six people to hospital; they have gone to the Royal Victoria Infirmary in Newcastle; three children and three adults.”
Emergency services included six ambulances, two paramedic rapid response vehicles and the air ambulance.
In a statement, the nearby Newcastle Central Mosque said: “Immediately after the Eid prayers, when the people were starting to leave the venue, a car collided with pedestrians.
“We pray and hope that all those affected recover soon fully.
“We thank the emergency medical services, the police and over 100 volunteers from the mosque for their quick response to the incident.
“We urge everyone to please pray for all those affected.”
Chi Onwurah, Labour MP for Newcastle Central, tweeted: “So sad, I was at the prayers earlier & there were so much joy & unity. Thinking of those affected by what I am told was terrible accident.”
‘Everyone locked arms’ – medical student Ahmad Ali
We were here for Eid. Everyone had just finished praying. The imam had finished his speech and everyone was talking to their families and getting some food.
Then we heard a commotion and screaming.
I ran up to the hill. A man got out of the passenger side. He seemed distraught.
Someone was trapped under the car and then everyone just pushed the car so they were free.
They were two children there, one of them – he was a boy about eight – was really badly injured,
There were about five doctors there so he had a lot of medical attention. We checked to see he had a pulse.
Everyone locked arms so there was a ring of locked arms around the injured people so they had space and the ambulances could get to them.
Everyone was distraught. I am very grateful it’s not an attack.
It’s very shocking to see a child injured like that. We are all hoping that he is fine, I just want to hear that.
BBC reporter Rachel Kerr at the scene
The helicopter hovering above the scene made it clear that this was a serious incident.
Police cars had stopped traffic on West Road and there were groups of people looking on – including those who had been at the Eid celebration and others who were coming to play football on the sports pitches.
Hundreds of people had been taking part in the Eid event on the large grass field behind the sports centre.
Police tape surrounded the scene where the car remained on a small hill at the top of the field. On the field itself were the signs of the Eid celebration.
In the immediate aftermath there was shock and confusion about what had happened, with many urging calm and for people to wait to hear the facts.
There was also a sadness that this had happened during such an important religious celebration.
Abdul Mahdoul, who was at the event, said: “We were wishing everyone happy Eid and suddenly we heard a lot of shouting and screaming. We didn’t know what it was.
“People were panicking. The police did a great job to calm the situation down.
“I just wish for the people to recover very quickly.
“We were worried because we were standing on that spot and we moved from there and then about 15 minutes later things happened.”
“It was a very happy atmosphere beforehand, but afterwards just chaos.”
Councillor Dipu Ahad said: “I hope there are no fatalities and my thoughts are with their families and other members who have been affected.
“We saw people crying and sobbing, it was like what you see in a horror movie, people were crying on the street, in corners.
“It was a real sad situation to see this and I think people were in confusion about what really happened.
“I had tears in my own eyes – it was a day of celebration for Muslims and others as well and it’s a very sad situation and I hope this never happens again.”
‘Heard screaming’ – Dr Afsar Madathil
I was at a car park when I heard screaming so I ran towards the community college just a couple of minutes from me.
When I went over I saw that there was a very young teenager covered in blood; another very young teenager also looked injured.
There was a middle-aged man outside the community college with facial injuries and blood all over his face.
The police were already at the scene. I had seen them earlier as they were there watching the prayers.
The police put the driver of the car in the back of the police van.
When I spoke to people at the scene that had seen what happened they said that she was exiting a car park and suddenly accelerated into a crowd of people.
I was with a few other doctors that came to help, but the police and paramedics were very quick and did not need our help.
The mayor of Newcastle was also there earlier for Eid celebrations.