London - Police arrested a man near London's Natural History Museum on Saturday after a vehicle apparently drove into pedestrians at a busy tourist spot, injuring a number of people.Witnesses and footage posted on social media suggest the man was pinned down on the ground near the Victoria and Albert Museum.Other footage and photographs showed a black car nearby with its door open and its bonnet severely damaged.An AFP reporter said crowds in the area, who include many families, fled screaming in panic. Witnesses reported by some media said they heard a loud bang.A police spokesperson said it was too soon to say whether it was terror related.Armed police were deployed to the scene, which is also near the Science Museum, and the whole area was subsequently cordoned off.Security is high in Britain after five terror attacks since March - four of them in London and one in Manchester - with the bloodshed claiming 35 lives.Three of the attacks in London involved the use of a vehicle to plough into pedestrians.Downing Street said Prime Minister Theresa May was being kept up to date with developments.'Everyone fled in panic' 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 later said the man had not been formally arrested, but had been detained. One witness, identified only as Katy, told LBC London radio she had seen two people injured, including a little boy who had hurt his leg and a woman who was not moving.A spokesperson for the Natural History 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."