Earlier in the day, a van rammed into pedestrians near the mosque in the northern London, killing one person and injuring eight others. The van's driver was detained by the people at the seen and later arrested by the Metropolitan Police.
"The Metropolitan Police are responding to a horrific terrorist attack on innocent people in Finsbury Park… 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. While this appears to be an attack on a particular community, like the terrible attacks in Manchester, Westminster and London Bridge it is also an assault on all our shared values of tolerance, freedom and respect," Khan wrote on Facebook.
The mayor added that additional police forces were deployed in the city "to reassure communities, especially those observing Ramadan."
