One shocked pedestrian wrote on Twitter: 'Just witnessed a auto drive into people in London.
Video footages from the site have floated on social media which showed a man held down on the ground by the police following the accident.
"Police have asked people to avoid the area while their inquiries continue", he said.
'It is believed that a number of pedestrians have been injured.
Officers had arrested a man at the scene and he was now being questioned.
Inmediaciones of the Natural History Museum #London Hombre reducido en el suelo antes de that llegue policía, no sabemos q pasa.
Reuters, however, quoted London Police as saying that they were keeping an "open mind" after the incident, contradicting an earlier comment ussed by the city's police force.
In London, a auto near Natural History Museum in Kensington district has been driven to a sidewalk and has captured several passers-by.
But in a later update, the Met said: "The incident is a road traffic investigation and not a terrorist-related incident".
According to reports, London Police have arrested a man from the scene.
Most of the injured suffered leg and head injuries.
"When I heard the crash I saw people running", he reported.
The terror threat level in the country is "severe", which means a terror attack is highly likely.
Crowds in the area, which is also home to the Victoria & Albert Museum and the Science Museum, fled screaming in panic, an AFP reporter said.
The collision raised concerns after a series of terror attacks this year in London involving vehicles ramming pedestrians.
Downing Street said that Prime Minister Theresa May is being kept up to date with developments.