Detectives have arrested a second man in London in connection with what they are calling a terrorist incident near Buckingham Palace.
Three police officers were injured on Friday night when they confronted a 26-year-old man who approached a police van in a restricted area outside Queen Elizabeth's London residence then reached for a 1 metre sword in his car.
The man, who repeatedly shouted "Allahu akbar!" ("God is great" in Arabic), was arrested on the scene.
Scotland Yard says a second suspect, a 30-year-old man, was detained on Sunday in west London on suspicion of involvement in terrorism. Officers were searching an address in the area as part of the probe.
The force added that a warrant has been granted to detain the first suspect until September 1.
Police previously said they believed the man was acting alone and were not looking for other suspects.
Palace officials declined to comment. British media reported that no members of the royal family were in the palace in London at the time.