A man carrying knives near the UK parliament has been wrestled to the ground by armed police and arrested on suspicion of terrorism offences.
Counter-terrorism officers detained the 27-year-old man on Parliament Street in London, near the parliament building and Prime Minister Theresa May's Downing Street office, during a stop-and-search in an ongoing security operation.
A witness described seeing two knives on the ground, one of which he described as a large bread knife.
Security remains tight outside Whitehall buildings following a terror attack on 22 March, when Khalid Masood killed four people when he drove along Westminster Bridge. He then got out of the car and stabbed PC Keith Palmer to death at the entrance to Parliament.
No one was injured in Thursday's incident and Mrs May was not at Downing Street at the time.
A French tourist who saw the arrest said the suspect looked "very calm". Another witness said the man was not shouting, or acting aggressively.
A police statement said: "The man was arrested on suspicion of possession of an offensive weapon and on suspicion of the commission, preparation and instigation of acts of terrorism. Knives have been recovered from him.
A Western security source said the man, from London, was known to counter-terrorism officers and the domestic intelligence agency MI5 before his arrest. Two hours after his arrest, police reopened streets in the Westminster district.
- BBC / Reuters