Police said the 48-year-old man who was driving the van has been arrested and taken to a hospital as a precaution.
Abdikadir Warfa said the van turned into an alleyway and hit a number of people before coming to a stop.
Another eyewitness, who gave his name as Athman, told AFP: "People were screaming: "It's a terrorist attack, it's an attack, this guy attacked us", and I had to run back and tried to save people who were still alive and giving water, helping the police".More news: Severe weather expected to affect 60 million Americans Monday
Others linked the attack to an increase in anti-Muslim hate crimes, particularly since the London Bridge rampage on June 3 that left eight people dead, which was claimed by the Islamic State.
Sister Nicola said she was "very sorry for what's happened", the Press Association reported.
- All of the victims were from the Muslim community, police said.
"We have continued to maintain regular patrols around a range of locations including Mosques and churches, and we are fully committed to working closely with all communities to keep them safe".
"The attack on Westminster bridge, the attack on London Bridge, the attack in Manchester, the attack last night - all of these are attacks on our shared values of our freedom, of tolerance and of respect, and terrorism is terrorism whether someone is inspired by an Islamist narrative or other forms of 'inspiration, '" he said. "We don't yet know the full details, but this was clearly a deliberate attack on innocent Londoners, many of whom were finishing prayers during the holy month of Ramadan", Khan said. "As a society we need to be more proactive and find better ways to defeat those who want to destroy our lives".More news: Iran sends a message with missile strike in Syria
Basu said officers in the immediate vicinity responded to the attack while additional support arrived within 10 minutes of the call. Early police caution about declaring the incident to be terrorist-related was interpreted by the community as discriminatory.
The incident followed a series of attacks in Britain.
Police officers guard a road leading to Finsbury Park Mosque the attack.
Searches are being carried out at a residential address, where Mr Osborne is listed as living, in the Cardiff area.
His attack killed five people.More news: New 'transforming' Forever Stamp commemorates August 21 total solar eclipse
On March 22, a man killed five people when he drove a vehicle into pedestrians on Westminster Bridge in London and stabbed a police officer.
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