The Metropolitan Police said they were treating as a “terrorist incident” the stabbing of a police officer at the Houses of Parliament in London on March 22.
A number of people were also injured when a car drove into a group of pedestrians on on Westminster Bridge.
This video, from BBC journalist David Scullion, shows an ambulance rushing towards the Houses of Parliament while an air ambulance lands in the background.
A full statement from the Metropolitan Police can be seen here.