But the Met said: "At this early stage of this investigation, no other suspects at the scene have been identified or reported to police, however the investigation continues".
A helicopter and several emergency vehicles were deployed at the scene and the area has been put under heavy police cordon.
"I'm totally shocked at the incident at Finsbury Park tonight".
"Over the past weeks and months, Muslims have endured many incidents of Islamophobia and this is the most violent manifestation to date. My thoughts are with those and the community affected by this very bad event".
The incident occurred just after midnight in the northern part of the city, near the Finsbury Park Mosque and the Muslim Welfare House.
Videos from the scene posted on Twitter showed crowds of people surrounding a police van that apparently held the driver of the van. She said a police officer was doing what looked like a "cardiac massage, as if they might have had a bad heart or something". "I just hope they did".
Arsenal Football Club's Emirates Stadium is located close by, while further up Seven Sisters Road is the green space of Finsbury Park, which opened in 1869 and gives the area its name. This year Ramadan began on May 26 and ends on Saturday June 24.
- Muslim Council of Britain releases a statement calling it a "terror attack".
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Locals massing at barriers, angry at police, people confused about what has happened.
A 48-year-old man has been arrested and taken to a hospital; the Metropolitan Police Service announced he would undergo a mental health assessment. As a community, everyone's a family here.
A Reuters witness saw at least one person being loaded into an ambulance.
"An advance trauma team from London's Air Ambulance has also been dispatched by vehicle", the statement said.
The head of the MCB, Harun Khan, said that the van had "intentionally" mowed down people who were leaving after the prayers for the holy month of Ramzan.
Several people were reportedly injured in London after a van hit a crowd in Finsbury Park.
Contributing: The Associated Press.