Update 14:30 p.m. 23rd March: Kurt Cochran, an American tourist in London with his wife to celebrate their 25th wedding anniversary, was named as a victim in the attack, reported The Guardian. Aysha Frade, a Spanish teacher, was also named on Thursday as having died in the attack.
Update 10:00 a.m. 23rd March: Metropolitan Police counterterrorism chief Mark Rowley confirmed that seven arrests were made in connection with yesterday's deadly attack. Police raided six addresses to make the arrests.
Rowley added that the attacker responsible for yesterday's bloodshed has been identified. He declined to reveal any information about the man, who was killed by police.
Four people have died in the terror incident in London, including an attacker and a police officer.
Update 17:00 p.m.: A doctor from St Thomas’ hospital has confirmed one woman has died, according to The Guardian. Another is said to have been pulled alive from the Thames. It was believed both were on Westminster Bridge at the time of the incident.
The London Ambulance Service has confirmed that they have treated at least ten patients on Westminster Bridge.
Update 15:55 p.m.: The Met Police said it is treating today's events as a terrorist incident until it knows otherwise.
Police are also asking people to avoid the following areas: Parliament Square; Whitehall; Westminster Bridge; Lambeth Bridge; Victoria Street up to the junction with Broadway and the Victoria Embankment up to Embankment tube.
The police said in a statement: "This is to allow the emergency services to deal with the ongoing incident. Officers - including firearms officers - remain on the scene and we are treating this as a terrorist incident until we know otherwise. We thank the public for their assistance."
Original story: A shooting and stabbing have taken place close to the Houses of Parliament in central London, according to reports. A police officer was stabbed and an alleged assailant was shot by armed police after a “serious incident”, the BBC reported.
Scotland Yard was called to a firearms incident on Westminster Bridge after several people were reported injured.
As many as 12 people were also reportedly injured after a car drove into them on Westminster Bridge before driving into the Palace of Westminster's railings, reported The Guardian. They are being treated at the scene.
Police have asked Transport For London for Westminster underground station to remain closed, reported the BBC. Staff inside Parliament have been advised to remain inside their offices.
This is a breaking news story which will be updated with more details as they emerge.