Van rams worshippers leaving London mosque, injuring 10

Shortly after midnight, the hired vehicle swerved into a group of people leaving prayers at the Muslim Welfare House and the nearby Finsbury Park Mosque in north London, one of the biggest in the country, witnesses said.

"This had all the hallmarks of a terrorist incident," said Neil Basu, senior national co-ordinator for counter-terrorism policing. "This was an attack on London and all Londoners."

If confirmed by the authorities as terrorism, it would be the fourth attack since March in Britain and the third to involve a vehicle deliberately driven at pedestrians.

The attack comes during the Muslim holy month of Ramadan when Muslims were attending special prayers. Abdulrahman Aidroos said he and his friends had been tending an old man who had suffered a heart attack when the van was driven at them.

"When he was running he was saying 'I wanna kill more people, I wanna kill more Muslims'," he told BBC TV. He said he had helped tackle the driver and pin him down with others until police arrived.

Basu thanked those who detained the driver, adding: "Their restraint in the circumstances was commendable."

The suspected van driver, aged 48, was arrested on suspicion of attempted murder and will be questioned by counter-terrorism officers.

"I would like to ... thank our Imam, Mohammed Mahmoud, whose bravery and courage helped calm the immediate situation after the incident and prevented further injuries and potential loss of life," said Toufik Kacimi, the chief executive of the Muslim Welfare House.

Police said the man who was being given first aid at the scene before the vehicle was driven into pedestrians had died but it was not clear whether his death was directly linked.

Eight others are in hospital, with two in a very serious condition. Two others were treated at the scene. The police said all were Muslims.

Usain Ali, 28, who was nearby, said he heard a bang and ran for his life.

"When I looked back, I thought it was a car accident, but people were shouting, screaming and I realised this was a man choosing to terrorise people who are praying," he told Reuters. "He chose exactly the time that people pray, and the mosque is too small and full, so some pray outside."

The attack comes at a time of political turmoil in Britain, as Prime Minister Theresa May, weakened by the loss of her parliamentary majority in a June 8 election, plunges into divorce talks with the European Union.

She has faced heavy criticism for her response to a fire in a London tower block last 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.

"All my thoughts are with the victims, their families and the emergency services on the scene," May said, adding that she would chair an emergency response meeting later on Monday.

The mayor of London, Sadiq Khan, said extra police had been deployed to reassure communities, especially those observing Ramadan. The leader of the opposition Labour Party, Jeremy Corbyn, in whose electoral area 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..

It also follows a suicide bombing at a pop concert in Manchester, northern England, in May which killed 22, while in March, 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.

Police had said hate crimes had risen after the London Bridge attack and they had stepped up their visible presence at places of worship.

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.

In a statement, Finsbury Park Mosque said it was a "callous terrorist attack" and noted it had occurred almost exactly a year after man obsessed with Nazis and extreme right-wing ideology murdered lawmaker Jo Cox, a former humanitarian aid worker.

Police said they were called just after 12:20 a.m. (2320 GMT Sunday) to reports of a collision on Seven Sisters Road, which runs through the Finsbury Park area of north London.

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.

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 after being convicted of 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 when attendance has greatly increased among worshippers from various communities, according to the mosque's website.

Members of the congregation in the two mosques in the area are mainly from North and West Africa.