British counterterrorism police on Saturday were investigating a man who was detained after he drove a car at police outside Buckingham Palace then "reached for a 4-foot sword," injuring three police officers.
The Metropolitan Police force said officers stopped a 26-year-old man who deliberately drove at a police van Friday night near Queen Elizabeth II's London residence, one of the city's top tourist attractions.
"Uniformed officers then confronted the driver of the vehicle and during that confrontation the driver reached for a 4-foot sword" in the car, said Dean Haydon, commander of the Metropolitan Police counterterrorism branch.
The suspect repeatedly shouted "Allahu akbar!" ("God is great" in Arabic), Haydon said. Three London police officers were slightly injured while struggling to arrest him, he added.
Police believed the suspect was acting alone and were not looking for other suspects Saturday. Counterterror officers were carrying out searches in Luton, north of London, where the suspect was from.
Kiana Williamson said she saw officers trying to wrestle a man out of a car that had stopped near the palace. In less than a minute, "the man had been restrained and looked almost unconscious by the side of the road," Williamson said.
The suspect was taken to the hospital for minor injuries and remained in custody in a London police station. No one other than him and the police officers was injured.
British media reported that no members of the royal family were in Buckingham Palace at the time.
British Prime Minister Theresa May and London Mayor Sadiq Khan thanked police for acting quickly to protect the public.
The police presence in London was stepped up because of the long Bank Holiday weekend and the annual Notting Hill Carnival, a busy street festival that attracts huge crowds.
Buckingham Palace did not comment on the incident and tours of parts of the palace that are open to the public in the summer were unaffected Saturday.
Last year, a man convicted of murder climbed a palace wall and was detained on the palace grounds while the queen was at home.