LONDON - London police say emergency services are outside the Natural History Museum in London after reports that a car has struck pedestrians. Police say a number of people have been injured and one person was detained at the scene. 

The crash happened at 2:20 p.m. on a day when the central London museum is usually teeming with pedestrians, including international tourists.

Photographs showed a dented silver car and a man being pinned to the ground outside the museum. It was not immediately clear if he was pinned down by police or others at the scene.

The London Ambulance Service was tending to the injured. There was no immediate statement on the number or severity of the injuries.

Shopkeepers in the immediate area were told to evacuate and police established a large security cordon around the area minutes after the incident, closing some roads. Police helicopters circled the scene overhead.

Police said they are working to establish the circumstances of the crash and more information will be provided once details are clear.

The Natural History Museum tweeted that there had been a “serious incident” outside the museum, which is located near the world famous Victoria and Albert Museum and other attractions.

Downing Street said British Prime Minister Theresa May was being briefed on the incident.

London’s official terrorist threat level has been set at “severe,” indicating an attack is highly likely.

There have been a series of terror attacks on London and Manchester this year, including vehicle attacks on pedestrians at Westminster Bridge and London Bridge.