AN attacker 'laughed' as he was arrested by police officers after a van ’intentionally’ swerved into a crowd of pedestrians near London’s Finsbury Park Mosque.

Metropolitan Police have confirmed one person has died and London Ambulance says it has conveyed eight injured to hospital.

Police confirmed the driver, a 48-year-old man, has been arrested on suspicion of attempted murder.

London Metropolitan Police’s Deputy Assistant Commissioner Neil Basu said all the victims were Muslim and two of the eight injured have been seriously hurt.

He said the attack unfolded while a man was receiving first aid from the public at the scene.

Camera Icon The van which ran into worshipers as they left the London mosque. Credit: PerthNow, AP Photo/Tim Ireland.

"Any causative link between his death and the attack will form part of our investigation. It is too early to state if his death was as a result of the attack," Basu said.

He confirmed the man acted alone and the crime is being investigated as a terrorist incident and the counter terrorist division was called in.

"Our thoughts are with all those affected by the incident at Seven Sisters Road and their family, friends and their communities," Basu said.

"No matter what the motivation proves to be, and we are keeping an open mind, this is being treated as a terrorist attack and the Counter Terrorism Command is investigating.

"This was an attack on London and all Londoners and we should all stand together against extremists whatever their cause."

Muslim man Rabie Rafa, 42, said: "He just laughed .

"They just killed people and he laughed.

"He had just ran people over up the sidewalk and killed innocent people.

"It was horrible to witness."

London police say one person has been detained after the incident, which caused "a number of casualties" just after midnight (7am AWST).

Eyewitness Zakriya James, 24, said he believed there were four attackers in what appears to have been a rented white delivery van. Three got away.

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The local said the van "ploughed" into people as they exited the mosque.

"The van just came through as people were walking towards where it was coming from," he said.

"They didn’t realise what was going on at first. People just started running.

"As far as I know there were four white males and three got away.

"It probably is a retaliation. People were coming out of their prayer. That says something."

Camera Icon Graphic: NewsCorp Credit: PerthNow

Reports suggest up to 10 people were hurt. The Sun reported that two are feared dead.

Prime Minister Theresa May has described the attack on worshippers as a "terrible incident".

"All my thoughts are with those who have been injured, their loved ones and the emergency services on the scene," she said.

A Metropolitan Police spokesman told CNN it’s "too early to say" if the London collision is a terror incident.

Up to 100 hundred people gathered outside the cordoned off zone blocking the mosque, with tensions high after the incident. Tensions are reportedly running high among the mainly Muslim crowd.

A group of men huddled together to condemn the "terror attack" outside the mosque, where people had been engaging in Ramadan.

"This is a terror attack!" a man shouted.

One person has been arrested.

There is a massive police response on the scene with riot vans, armed personnel and a helicopter.

A man, who asked not to be named, said his uncle had been hit by the van.

"I have not heard from him but my friend told me he’d been hurt," he told News Corp.

"The van just drove up and hit them out of nowhere.

"They didn’t see it coming.

"They knew there would be people there.

"They were white extremists."

The city is on edge after the London Bridge terror attack on June 3, where three Islamic terrorists killed eight people, including two Australians.

The killers mowed down pedestrians on the famous bridge before going on a stabbing frenzy at nearby Borough Market.

On March 22, Briton Kahlid Masood ran over pedestrians on Westminster Bridge killing five people and injuring 50.

The latest attack happened just days after an horrific fire at Grenfell Tower in west London, which took more than 58 lives.

Metropolitan Police said officers were called just after midnight on Sunday to an incident on Seven Sisters Road.

"Officers are on the scene with other emergency services," he said. "There are a number of casualties being worked on at the scene. There has been one person arrested. Enquiries continue."

London Ambulance reported it has sent ’a number’ of resources to the Seven Sisters Road ’incident’.

It is understood that the pedestrians were hit outside a local Muslim welfare house.

Photos purporting to show the white van used in the attack show it was rented from a company in Wales.

A Department of Foreign Affairs and Trade spokeswoman confirmed the Australian High Commission in London was making urgent enquiries with local authorities to determine whether any Australians had been affected in the Finsbury Park incident.

The Department advised any Australians with concerns for the welfare of family and friends in the region to contact them directly first and to then call DFAT’s 24 hour Consular Emergency Centre on 1 300 555 135 or +61 2 6261 3305 if they still had concerns.

The Muslim Council of Britain (MCB), an umbrella body, said on Twitter: "We have been informed that a van has run over worshippers as they left #FinsburyPark Mosque. Our prayers are with the victims.

Harun Khan, the general secretary of the MCB, tweeted that the van had "intentionally" run over people leaving night prayers held during the holy month of Ramadan.

Khan said he was "shocked and outraged to hear a van has intentionally run over worshippers leaving Ramadan prayers".

Mohammed Shafiq of the Ramadhan Foundation, a Muslim organisation which speaks out against extremism, said: "I utterly condemn the senseless and evil van attack against Muslim worshippers outside the Finsbury Park Mosque in London.

"According to eyewitnesses this was a deliberate attack against innocent Muslims going about their life.

"We should make clear that if this attack is confirmed as a deliberate terrorist attack then this should be classed as an act of terrorism.

"The British Muslim community requires all decent people to stand with us against this evil violence.

"Rampant Islamaphobia has been on the rise for a number of years and those on the far right have perpetuated hatred against Muslims.

"They should be called out for their hatred."

Eyewitnesses have told LBC radio that the van approached "slowly and intentionally accelerated into crowded cafe outside a mosque".

Another witness told the station: "I saw police giving CPR, getting the heart going again and another guy on the floor."

Local resident Mohammed Mudhar, 28, said his family were inside the mosque at the time.

"I ran here to check they were OK," he said.

"Luckily they weren’t hit. They did this at a time they had thought through perfectly. It was right as they had finished prayer and were coming out to break their fast and eat.

Camera Icon Multiple views of the scene on Seven Sisters Road near London’s Finsbury Park Mosque. Credit: PerthNow

"They hit about 10 people. The timing was spot on. It makes me very scared. We’re just normal people."

A witness told LBC radio people had been drinking coffee at a nearby cafe after leaving the mosque after Tarawih prayers performed for the Islamic holy month of Ramadan.

The holiest month of the Islamic calendar, Ramadan will finish this coming Saturday, June 24.

Another caller told LBC her sister was at the scene when the incident happened.

The woman said her sister described it as "something from a horror movie, everyone running everywhere".

She didn’t realise what was going until she saw people on the ground.

Camera Icon General view near Finsbury Park Mosque where a van collided with pedestrians. Credit: PerthNow, Lexie Cartwright

One witness told the BBC at least three people were seriously injured. "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’," a 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. I didn’t see the attacker himself, although he seems to have been arrested, but I did see the van."

Eyewitnesses reported seeing bystanders wrestle a suspect to the ground and pin him down until officers arrived.

Mohammed Kozbar, chairman of Finsbury Park mosque, told The Sun: "Whoever did this, he did it to hurt people and it’s a terrorist attack.

"We call it a terrorist attack as we called it in Manchester, Westminster and London Bridge. The van drove over people who were leaving late prayers. They were gathering in Seven Sisters Road.

"I heard there are fatalities but I don’t want to jump to conclusions. My concern now is the casualties who have been affected."

MOSQUE’S RADICAL HISTORY

Finsbury Park Mosque has been known to have served as a clearing house for radical Muslims after cleric Abu Hamza arrived as imam in 1997.

Al Qaeda operatives including "shoebomber" Richard Reid and Zacarias Moussaoui attended the mosque.

In 2003 the Mosque was raided by the police and shut down. It was then reclaimed in 2005 by the local Muslim community with the help of the Muslim Association of Britain (MAB).

Camera Icon Crowds gather outside the scene where a van collided with pedestrians in London. Credit: PerthNow, Lexie Cartwright

Hamza, known as the Hook Hand, is an Egyptian cleric who preached Islamic fundamentalism and militant Islamism from the London mosque until he was arrested in 2004 after a US request to extradite him to face terrorism charges.

He was later charged by British authorities with 16 offences for inciting violence and racial hatred. In 2006, a British court found him guilty of inciting violence, and sentenced him to seven years’ imprisonment.

On 5 October 2012, after an eight-year legal battle, he was extradited from the UK to the US to face terrorism charges and on 14 April 2014 his trial began in New York.

On 19 May 2014, Hamza was found guilty of eleven terrorism charges by a federal jury in Manhattan. On 9 January 2015, he was sentenced to life in prison without the possibility of parole.