"When we look at Islamist-based terrorism, the actors received counselling and instruction from like-minded people", he said.
Metropolitan Police deputy assistant commissioner Neil Basu confirmed that the incident was being treated as a "terrorist attack". A police photographer records the scene at Finsbury Park in north London, where a vehicle struck pedestrians in north London Monday, June 19, 2017.
"Today we come together - as we have done before? to condemn this act and to state once again that hatred and evil of this kind will never succeed", she said.
"This was an attack on Muslims near their place of worship".
The driver drove the van into worshippers close to Muslim Welfare House in Finsbury Park as they were gathered to help an elderly man who had collapsed. "We will not let this happen", she said.
To the north, Manchester was hit by a deadly attack May 22 when a suicide bomber killed 22 people at an Ariana Grande concert.
- May 22, 2013: Two al-Qaida-inspired extremists run down British soldier Lee Rigby in a London street, then stab and hack him to death.
"It was a van that mounted the pavement as men and women were leaving the mosque to go home to their families and friends and their loved ones", Jackson said.
A statement released by the Muslim Council of Britain (MCB) condemned what it described as a "terror attack".
"Citizens agitated in Finsbury Park - "where is the BBC?"
Mamhoud was joined by several other bystanders who formed a protective ring around the suspect until police hustled him into the back of a van, the Evening Standard reported.
One witness described being surrounded by bodies in the wake of the attack outside the Muslim Welfare House, yards from the mosque.
One man was pronounced dead at the scene and eight people were taken to hospital. A local imam, Mohammed Mahmoud, said he and others shielded the man until police could take him away.
Police said they had deployed extra officers "to reassure communities, especially those observing Ramadan".
The Mayor of London, Sadiq Khan, told Sky News earlier on Monday that the imam's actions in "calming things down" were "what I'd expect from a good faith leader, from a good Muslim leader".
"While this appears to be an attack on a particular community, like the bad attacks in Manchester, Westminster and London Bridge, it is also an assault on all our shared values of tolerance, freedom and respect", Khan said.
The attack laid bare the frustrations of Muslims who feel they've been unfairly equated with the extremists who carry out atrocities in the name of Islam. "There is far more that unites us than divides us", he added.
Hours after the incident, as dawn broke, a large and angry crowd remained in the streets. The leader of the opposition Labour Party, Jeremy Corbyn, said he was "totally shocked". But in the past decade, the mosque has transformed its image, with its leadership outspoken in advocating interfaith harmony.
London Underground staff left a defiant message for commuters following the Finsbury Park attack.
One witness told CNN it was clear that the attacker at Finsbury Park had deliberately targeted Muslims.