London - Police arrested a man near London's Natural History Museum on Saturday after a vehicle apparently drove into pedestrians, injuring a number of people.Crowds in the busy tourist spot in South Kensington, which is also home to the Victoria & Albert Museum and the Science Museum, fled screaming in panic, an AFP reporter said.Armed police were at the scene, and a video posted on Twitter showed a man being held down on the road next to a black car that appeared to have crashed.Security is high in Britain after five terror attacks in six months - four of them in London and one in Manchester - with the bloodshed claiming 35 lives.London's Metropolitan Police said they were called to the scene at 14:21 (13:21 GMT) after reports of a collision."It is believed that a number of pedestrians have been injured. A man [no further details] has been arrested at the scene," the police said in a statement."Enquiries to establish the circumstances and motive are under way."A spokesperson for the museum told AFP: "I can confirm that there has been a vehicle collision with pedestrians on our Exhibition Road entrance."One witness, who gave his name only as Leonard, told AFP: "I was near South Ken station and there were many police."Suddenly a police woman officer shouted at the crowd to run, and everybody fled in panic, many people screaming."