UK Parliament terror attack

Emergency services at the scene outside the Palace of Westminster, London.

Armed police officers enter the Houses of Parliament in London after the House of Commons sitting was suspended as witnesses reported sounds like gunfire outside.

Conservative Member of Parliament Tobias Ellwood helps emergency services attend to an injured person outside the Houses of Parliament, London.

Emergency services staff provide medical attention close to the Houses of Parliament in London.

Police vehicles are seen near Whitehall in London, Britain.

Police cordon off the street outside the Houses of Parliament in London, Britain.

Ambulances and police vehicles are seen near the Houses of Parliament, in London, Britain.

Emergency services staff and forensic officers work on Westminster Bridge in London, Britain.

Police cordon off the street outside the Houses of Parliament in London, Britain.

Two policemen stand guard outside the Houses of Parliament in London, Britain. Four people have been killed, including the stabbed officer and a male terrorist, and at least 20 injured in an attack on the Houses of Parliament afternoon in a terrorist attack.