Many of the people hurt after a vehicle struck pedestrians in north London are thought to have just finished worshipping at the Finsbury Park Mosque.
Witnesses described seeing a white van drive into people on Seven Sisters Road.
Delivery driver Mohammed Abdullah, who was on a bike about three cars behind the incident, told Sky News he saw the van take a sudden left turn.
"I think he done it on purpose. I was on a ped. He was about three cars in front of me. He came in a bus lane and took a sharp left," he said.
"He went on top of the people. He actually ran them over. It was a white van.
"There was three of them. Two of them ran away. The other was held at the scene until the police came. Some people wanted to beat him up.
"I've seen about six or seven people on the floor. Most of them was male. It was exactly the same time as the prayers finished. As soon as it finished, this guy came. I think (the road he took) is a blocked road - It's not even a through road.
"The other two got away. They must be somewhere around Finsbury Park. They ran away somewhere."
He said the man arrested did not say anything.
"He had a tattoo on his back. He was not ill. He was not drunk. He got arrested by five or six police officers. They took him away. They never dropped him or nothing."
Finsbury Park resident Cynthia Vanzella said she saw police giving emergency medical treatment to victims after the incident which happened just after midnight.
She told Sky News: "I heard a lot of shouting and panic. It was really ugly. I could see at least two people on the floor not moving and police officers trying to do cardiac massage on them."
One man, who gave his name as Mohin, said his cousin was caught up in the incident.
The 32-year-old told the Press Association: "There were a lot of people in the street, crossing the street, going to mosque for prayers, for forgiveness, just to pray and go home and eat.
"They are doing their usual daily routine - they did not expect a van coming out of nowhere hitting them.
"It was around 11.30pm, 12-ish. I've been living here all my life. As a community, everyone's a family here.
"I initially thought it was my cousin."