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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. AP
In this image taken from video, police officers gather around a car adjacent to Houses of Parliament in London. Five people were killed, including the assailant, and 40 others were injured in what Prime Minister Theresa May condemned as a "sick and depraved terrorist attack." AP
Emergency services staff provide medical attention close to the Houses of Parliament in London. Lawmakers, lords, staff and visitors were locked down after the assailant was shot by police within the perimeter of Parliament. AP
Conservative Member of Parliament Tobias Ellwood (centre) helps emergency services attend to an injured person outside the Houses of Parliament, London. A doctor who treated the wounded from the bridge said some had "catastrophic" injuries. AP
An Air Ambulance comes in to land as emergency services attend to injured persons outside the Houses of Parliament, London. Metropolitan Police counter-terrorism chief Mark Rowley said police believed there was only one attacker, "but it would be foolish to be overconfident early on." AP
An injured man sits covered with a blanket as emergency services staff provide medical attention to injured people on the south side of Westminster Bridge, close to the Houses of Parliament. The threat level for international terrorism in the UK was already listed at severe, meaning an attack was "highly likely." AP
London has been a target for terrorism many times over past decades. Just this weekend, hundreds of armed police took part in an exercise simulating a "marauding" terrorist attack on the River Thames. AP