A man with a knife has been arrested near Buckingham Palace in an incident Scotland Yard said was not believed to be terror related.
The Queen, who on Tuesday hosted a garden party celebrating the efforts of those who make positive impacts on their community, is in residence.
Footage of the arrest on Wednesday morning was posted online.
The Changing the Guard ceremony at Buckingham Palace was cancelled on Wednesday to redeploy police officers in the wake of the Manchester attack, the Ministry of Defence said.
The military will be providing armed guards for key locations across London including Buckingham Palace, Downing Street, the Palace of Westminster and embassies, Scotland Yard announced.