One man died but since he was receiving first aid at the site before the vehicle hit, police say it is not clear whether his death was directly linked. The driver of the van, identified only as a 48-year-old white man, was arrested by the police.
A van ploughed into worshippers outside the Muslim Welfare House near Finsbury mosque in London mosque on Monday. At least 10 people were injured in what the Muslim Council of Britain said was a deliberate act of Islamophobia and the authorities are investigating as a terror attack.
One man, who was already being given first aid at the scene before the vehicle was driven into pedestrians, has died but police said it was not clear whether his death was directly linked. Eight others are in the hospital, with two in a very serious condition.
The driver of the van, a white man aged 48, was detained by members of the public and then arrested by the police.
Attack targeted the ordinary and the innocent: May
British Prime Minister Theresa May while addressing the nation said hatred and evil would never succeed.
She said police had confirmed the incident was being treated as a potential terrorist attack.
"This morning, our country woke to news of another terrorist attack on the streets of our capital city: the second this month and every bit as sickening as those which have come before," she said outside her Downing Street office.
"It was an attack that once again targeted the ordinary and the innocent going about their daily lives, this time British Muslims as they left a mosque after prayers."
May chaired an emergency response meeting on Monday.
The early assessment of police is that the attacker acted alone, she said.
She said extra police resources would be deployed to provide reassurance and said Britain had been far too tolerant of all forms of extremism in the past.
Meanwhile, Ben Wallace, junior minister for security in the Home Office, or interior ministry told Sky News that the man arrested by the police was not known to the security services in terms of far-right extremism.
Cause of death to be determined
British police said it was too early to say whether the one death was due to the van attack.
"The attack unfolded as a man was already receiving first aid at the scene, sadly that man has died," Neil Basu, senior national coordinator for counter-terrorism policing, said.
Police said the arrested van driver would undergo a mental health assessment in due course.
The London Ambulance Service said it had taken eight people to the hospital, while two were treated at the scene.
The leader of the opposition Labour Party, Jeremy Corbyn, in whose constituency the attack took place, said he was "totally shocked".
I'm totally shocked at the incident at Finsbury Park tonight. pic.twitter.com/1ffKijNs73— Jeremy Corbyn (@jeremycorbyn) June 19, 2017
The Muslim Council of Britain, a cross-sect umbrella group, said the incident was the most violent manifestation of Islamophobia in Britain in recent months and called for extra security at places of worship as the end of Ramadan nears.
"It appears that a white man in a van intentionally ploughed into a group of worshippers who were already tending to someone who had been taken ill," the Council said in a statement.
Mayor of London Sadiq Khan said extra police had been deployed to reassure communities, especially those observing Ramadan, describing the attack as "an assault on all our shared values of tolerance, freedom and respect".
Police said they were called just after 12:20 am (2320 GMT ) on Sunday to reports of a collision on Seven Sisters Road, which runs through the Finsbury Park area of north London.
"From the window, I started hearing a lot of yelling and screeching, a lot of chaos outside … Everybody was shouting: 'A van's hit people, a van's hit people'," one woman who lives opposite the scene told the BBC.
"There was this white van stopped outside Finsbury Park mosque that seemed to have hit people who were coming out after prayers had finished."
The incident comes just over two weeks after three attackers drove into pedestrians on London Bridge and stabbed people at nearby restaurants and bars, killing eight.
It also comes at a time of political turmoil, as Prime Minister May plunges into divorce talks with the European Union weakened by the loss of her parliamentary majority in the June 8 election.
She has faced heavy criticism for her response to a fire in a London tower block on Wednesday which killed at least 58 people, and for her record on security after a series of attacks blamed on extremists in recent months.
One witness told CNN it was clear that the attacker at Finsbury Park had deliberately targeted Muslims.
"He tried to kill a lot of people so obviously it's a terrorist attack. He targeted Muslims this time," the witness, identified only as Rayan, said.
Other witnesses told Sky television that the van had hit at least 10 people.
Miqdaad Versi, the Council's assistant secretary general, said the van had deliberately swerved into a group of people who were helping a man who was ill and had fallen to the ground.
"Basically, a van swerved into them deliberately," Versi said.
He said the driver had run out of the van but a group of people caught him and held him until police arrived.
Britain has been hit by a series of attacks in recent months, including the van-and-knife attack on London Bridge on June 3.
On March 22, a man drove a rented car into pedestrians on Westminster Bridge in London and stabbed a policeman to death before being shot dead. His attack killed five people.
On May 22, a suicide bomber killed 22 people at a concert by American pop singer Ariana Grande in Manchester in northern England.
The attacks were a factor in campaigning ahead of the June 8 election, with May criticised for overseeing a drop of 20,000 in the number of police officers in England and Wales as interior minister from 2010 to 2016.
She was also criticised for keeping her distance from victims of the Grenfell Tower blaze during her visit to the charred remains of the 24-storey building.
She said on Saturday the response to the fire, in which at least 58 people were killed on Wednesday, had been "not good enough".