Five people, including a London police officer who was stabbed and the alleged assailant, were killed in a terror attack that saw more 40 people injured outside the Parliament building on Wednesday in an act described as "sick and depraved" by British Prime Minister Theresa May. "Meanwhile, the Islamic State group claimed responsibility Thursday for an attack by a man who plowed an SUV into pedestrians on a crowded London bridge and then stabbed a police officer to death on the grounds of Britain's Parliament.The attacker was born in Britain and known to authorities who had once investigated him for links to religious extremism, British Prime Minister Theresa May said Thursday in a sweeping speech in which she also encouraged Britons to go about their lives.The Islamic State group said through its Aamaq News Agency that the attacker was a soldier of the Islamic State who "carried out the operation in response to calls for targeting citizens of the coalition" of countries fighting IS in Syria and Iraq. In addition to the police officer and the attacker, who was shot by police, two people died on Westminster Bridge and at least 30 others were injured, seven critically.British officials did not release the attacker's identity or confirm a link with the Islamic State group, though May did say it would be wrong to describe the attack as "Islamic" extremism. Westminster attack: Police officer among four dead in terror attack

Westminster attack: Police officer among four dead in terror attack

Four people are dead after a knifeman ploughed a car into crowds outside the Houses of Parliament then stabbed a police officer in a major terror attack. Mark Rowley, the acting deputy commissioner of the London Metropolitan Police, earlier revised down the number of dead to three — Keith Palmer, 48, the police officer with 15 years of service who has stabbed outside Parliament, and two civilians — a woman in her 40s and a man in his 50s. WARNING: GRAPHIC IMAGES – PHOTOS FROM LONDON TERROR ATTACK

Police said a vehicle mowed down pedestrians on London's Westminster Bridge, leaving more than a dozen with injuries described as catastrophic.
An attacker carries out a vehicle-ramming attack outside the Houses of Parliament in London, before stabbing a police officer and subsequently being shot by security forces. Including the attacker, there are at least four people dead.