The deadly van attack near a mosque in north London had "all the hallmarks of a terrorist incident," police say.
The man suspected of being the driver has been arrested on suspicion of attempted murder, and no other suspects have been identified or reported to police, Deputy Assistant Commissioner Neil Basu told reporters on Monday.
All the victims were Muslim, Basu said.
One person was killed and eight people were taken to hospital and two others were treated at the scene.
Basu said at least two of the injured were in serious condition.
The suspect "was very quickly and calmly given over to the police," Basu said, as he praised the community.
It shows that "Londoners will act together to protect themselves, and will do so in a way that doesn't feed into terrorists' hands."
He said it was too early to say whether the person's death near the mosque was due to the attack by the van driver who ploughed into worshippers.
"The attack unfolded as a man was already receiving first aid at the scene, sadly that man has died," Neil Basu, senior national co-ordinator for counter-terrorism policing, said.
"Any causative link between his death and the attack will form part of the investigation. It is too early to say if his death was as a result of this attack."
