Two police officers have been injured while arresting a man armed with a knife outside Buckingham Palace.
'Two police officers suffered minor injuries during the course of detaining the man.
Natalie Wood wrote: "Police still being called into Buckingham Palace".
While the police were trying to place him under arrest the man attacked the officers.
"Given what has happened in London in recent months with terrorist attacks, police have significantly stepped up their patrols, particularly around central London".
The police response to the incident was rapid, and the area was soon secured by dozens of officers and police vehicles.
Social media posts from the scene showed a huge police presence swarm around the area, with drivers blocked from approaching one of Britain's most popular tourist attractions. They have not been taken to hospital.
"Officers are on scene at the Mall outside Buckingham Palace".
"No other persons have been reported injured".
The Queen was not in Buckingham Palace at the time of the incident as she is staying at her Scottish residence Balmoral.
Meanwhile, federal prosecutors claimed that the knifeman who attacked two soldiers in Brussels on Friday was shot dead.
The soldiers - who suffered injuries to their face and hand - opened fire on the attacker as the 30-year-old man, believed to be from Somalia, charged at them with a large bladed weapon.