"This is very worrying to the Muslim community".
Hatred and evil of this kind will never succeed.
A police officer detains a man near the scene of the attack.
"Someone called me and said it was him and I said "It can't be".
Eyewitness Abdulraman Aidroos told Anadolu Agency the "white British man" had shouted "I am going to kill Muslims".
Police said the 48-year-old man who was driving the vehicle has been arrested and taken to a hospital as a precaution. "Their restraint in the circumstances was commendable", said deputy assistant commissioner Neil Basu, the senior national coordinator for counter terrorism.
Mosque imam saves driver from angry mob after terror attack
He was taken to a hospital as a precaution, where he'll receive a mental health assessment, according to the statement. She said her thoughts were with the injured, their loved ones and emergency officials who responded to the incident.
Mamhoud was joined by several other bystanders who formed a protective ring around the suspect until police hustled him into the back of a van, the Evening Standard reported.
London Mayor Sadiq Khan, the city's first Muslim mayor, called the incident a "horrific terrorist attack", which was "clearly a deliberate attack on innocent Londoners, many of whom were finishing prayers during the holy month of Ramadan".
Police in the United Kingdom are investigating possible links to terrorism after a van was driven into a crowd of people outside Finsbury Park Mosque in London in the early hours of Monday morning.
Transportation officials said roads were being closed in the area. That incident, plus the four attacks, have stretched British authorities and left May's government, which suffered losses in a snap election, reeling.
Vehicles have also been also used to attack the public on London's Westminster Bride, in Nice, and in Berlin.
Eight people were killed on June 3, when a van drove into people on London Bridge before three attackers stabbed victims around nearby Borough Market.
Police said extra personnel had been deployed to reassure Muslim communities in London and security outside mosques would be reviewed.