A man has been arrested outside Buckingham Palace in London, England, for allegedly assaulting two police officers. Police would only confirm that the man had a knife.
The alleged offender was held just after 8.30pm on Friday evening on suspicion of assault and grievous bodily harm.
Buckingham Palace is not on "lockdown", Metropolitan Police said.
Twitter user Amir Jan Malik wrote: "Stuck outside Buckingham palace with many armed police officers".
The 25-year-old said: "I was walking toward The Mall and St James's Park when I saw police rush down toward the palace in great numbers".
London Ambulance Service treated the two injured officers at the scene.
People said they have been directed away from the area.
No other injuries have been reported.
Officers remain at the scene and inquiries are ongoing.
The Telegraph reports the Queen was not in residence when the attack happened and the palace is in lockdown.