London's Metropolitan Police commissioner announced that the Muslim community attending prayers will see police protection in the wake of a man driving a van into a crowd of people outside a mosque in what authorities called a terrorist attack.

One person who had been receiving first aid before the attack, which occurred just after midnight prayers on Monday, died on the scene, but it is unclear at this time whether he died as a result of what took place.

At least 11 people were injured in the incident, and the London Ambulance Service said in a statement today that it took nine patients to three hospitals in the city and treated others at the scene for minor injuries.

A 48-year-old man was arrested at the scene on suspicion of attempted murder. No other suspects have been identified, police said.

Metropolitan Police Commissioner Cressida Dick said the incident, near Finsbury Park in the north of London, was "quite clearly an attack on Muslims."

She later told reporters Monday. "The people in the Muslim community attending prayers will see their police protecting them in the coming days and nights."

Prime Minister Theresa May called the incident, which mirrored other high-profile terrorist attacks in which vehicles were used as weapons, "every bit as sickening as those that have come before."

London Mayor Sadiq Khan said "terrorism is terrorism."

Forensic and police officers attend to the scene after a vehicle collided with pedestrians in the Finsbury Park neighborhood of North London, June 19, 2017.

"It doesn't matter whether you're inspired by a perverse force of Islam -- a perverse version of Islam -- or by you're inspired by some other motives to try and terrorize others. The intention is the same, to divide communities, to make us stop leading the lives that we do," he said.

Khan said there has been a spike in hate crime, including against Muslims, since the recent London bridge attack.

Eyewitnesses interviewed by ABC News said people had gathered outside the mosque after prayers when the van drove into them.

A man identified as Jermain Jackman told the BBC the sidewalks were "packed with people walking home" when the incident occurred.

"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.

The Muslim Council of Britain called the incident a "terror attack" and the "most violent manifestation" of Islamophobia.

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