Police guard a street in north London where the van hit pedestrians.
The suspect, who lived in Wales and was identified as Darren Osborne, was held by a crowd who had witnessed him drive a van into a group of Muslim faithful, Efe newsreported.
The use of a vehicle to mow down pedestrians drew horrifying parallels with the June 3 attack in London, when three men drove a van into pedestrians before embarking on a stabbing spree, and with another auto and knife rampage in Westminster in March.
Jeddah - An official source at the Foreign Ministry condemned terrorist attack on worshipers near the Finsbury ParkMosque north of London. The man was arrested on suspicion of attempted murder and police said they believed he had acted alone.
Osborne injured at least 10 people and killed one; eight remain in hospital in critical condition.
"This was a horrific attack on innocent people going about their daily lives, many of them worshippers leaving evening prayers".
Describing the attack, Hussein Ali told news.com.au that Osborne "chose to get as much casualties as possible; he came exactly at the time to get as much people as he wanted". "When he was on the floor, the guy asked 'why do you do that?' He said 'Because I want to kill many Muslim people".
Dave Ashford, 52, said: "Someone called me and said it was him and I said "It can't be".
"This is an extremely hard time for our city, but I urge all Londoners to remain calm and vigilant".
"For that reason this guy is still alive today", Mohammed, 29, told The Guardian.
"The driver of the van - a man aged 48 - was found detained by members of the public at the scene", according to the police report.
A previous version of this story has been corrected to show that the identification of the suspect was reported by British media, not police.
"There was a mob attempt to hurt him, so we pushed people away from him until he was safely taken by police", Mahmoud said.