A van has mowed down pedestrians outside a mosque in London causing a “number of casualties”.

Local police arrested one person shortly after midnight local time on Seven Sisters Road in Finsbury Park.

London Ambulance Service sent “a number of resources” to the incident.

“We have sent a number of ambulance crews, advance paramedics and specialist responses teams to the scene,” the ambulance service said.

“An advance trauma team from London’s Air Ambulance has also been dispatched by car.

“We are working closely with other members of the emergency services at the scene.

“Our priority is to assess the level and nature of injuries and ensure those in the most need are treated first and taken to hospital.”

“More information will follow when we have it.”

Witnesses at the scene have described it as “horrible” and “hell”.

There are reports that the pedestrians were targeted after leaving a mosque following prayers for the Islamic holy month of Ramadan.

The Muslim Council of Britain has tweeted its support for the victims.

Here’s a look at other posts coming through on social media from the scene

Here are some of the photos of the emergency services attending the incident

There has been a spate of terrorist attacks in London in recent weeks.

On June 3, eight people were killed and another 50 were injured when three Islamist militants drove into pedestrians on London Bridge and stabbed people at Borough Market.

On May 22, a suicide bomber killed 22 people at a concert by American pop singer Ariana Grande in Manchester.

On March 22, a man killed five people after he drove a car into pedestrians on Westminster Bridge in London and stabbed a policeman to death. He was shot dead at the scene.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.