Updated 11pm

A man has been arrested outside Buckingham Palace in London on suspicion of grievous bodily harm and assault after two officers were injured, Scotland Yard said.

Scotland Yard said the officers suffered minor injuries in the course of arresting the man on Friday night. No other people were injured, the force wrote on Twitter.

Police said the man was stopped outside the royal grounds in possession of a knife at around 8.35pm.

The London Ambulance Service attended to treat the injured men but they were not taken to hospital.

READ: Prince Andrew confronted by police on palace grounds

Images posted online showed a heavy police presence outside the palace, with emergency vehicles packing out the road.

Armed police were reported to be on the scene.

Twitter user Amir Jan Malik wrote: "Stuck outside Buckingham palace with many armed police officers. Heavy rifles on display traffic at a halt."

READ: In 2013, a palace break-in sparked a security review

Witness Nicole Kyle was walking home when she saw armed police swoop on the scene and quickly put up a cordon.

The 25-year-old consultant told the Press Association: "I was walking toward The Mall and St James's Park when I saw police rush down toward the palace in great numbers.

"As we got further down The Mall we saw armed police outside a police van, at which point we were able to walk closer to the palace still, where we were eventually stopped by a cordon.

"All we were told was that there's been an incident.

"A few minutes later police came by to have us clear the area and move further away from the palace.

"We then saw that police had expanded the cordon. It looks like the cordon is continuing to expand."

The Metropolitan Police said it was too early to know whether the incident was terror related.

A Buckingham Palace spokeswoman said it does not comment on security issues.