A van plowed into worshippers leaving a London mosque Monday, killing at least one person and injuring 10 others in what witnesses said was a deliberate attack on Muslims.

The hired vehicle swerved into a group of people leaving prayers shortly after midnight at the Finsbury Park Mosque, one of the biggest in the country, witnesses said. The attack comes during the Muslim holy month of Ramadan.

“This big van just came and went all over us,” witness Abdulrahman Saleh Alamoudi told BuzzFeed News. “He was screaming… ‘I’m going to kill all Muslims.’ “

British Prime Minister Theresa May said police had confirmed it was being treated as a potential terrorist attack and said she would chair an emergency response meeting later on Monday.

“All my thoughts are with the victims, their families and the emergency services on the scene,” she said.

Police said one man was pronounced dead at the scene and that the van driver, aged 48, had been detained by members of the public before being arrested. The driver would undergo a mental health assessment in due course, police said.

Eight people were taken to hospital, while two were treated at the scene.

The 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.”

The leader of the opposition Labour Party, Jeremy Corbyn, in whose constituency the attack took place, said he was “totally shocked.”

The incident comes just over two weeks after three Islamist militants drove into pedestrians on London Bridge and stabbed people at nearby restaurants and bars, killing eight.

The Muslim Council of Britain said Monday’s attack was the most violent manifestation of Islamophobia in Britain in recent months, and called for extra security at places of worship.

“It appears that a white man in a van intentionally plowed into a group of worshippers who were already tending to someone who had been taken ill,” the council said in a statement.

Police said they were called just after 12:20 a.m. 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 attack comes at a time of political turmoil in Britain, as Prime Minister May plunges into divorce talks with the European Union weakened by the loss of her parliamentary majority in a June 8 election.

She has faced heavy criticism for her response to a fire in a London tower block Wednesday which killed at least 58 people, and for her record on security after a series of attacks blamed on Islamist militants 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. The Evening Standard newspaper said the van appeared to have been rented in Wales, although there was no immediate confirmation of this from the authorities.

Miqdaad Versi, assistant secretary-general of the Muslim Council of Britain, 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, citing a witness.

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 criticized for overseeing a drop of 20,000 in the number of police officers in England and Wales while she served as interior minister, from 2010 to 2016.

She was also criticized for keeping her distance from angry residents during her visit to the charred remains of the 24-story Grenfell Tower. She said on Saturday the response to the fire had been “not good enough.”

The Finsbury Park Mosque gained notoriety more than a decade ago for sermons by radical cleric Abu Hamza al-Masri, who was sentenced to life in a U.S. prison in January 2015 for his conviction on terrorism-related charges.

A new board of trustees and management took over in February 2005, a year after Abu Hamza was arrested by British police. Since then attendance has greatly increased among worshippers from various communities, according to the mosque website.