The extremist "Islamic State" group (IS) said Thursday via its news agency Aamaq that the attacker who rammed pedestrians on Westminster Bridge and stabbed a police officer outside Parliament on Wednesday was one of its "soldiers." On Thursday, police named the man as 52-year-old Khalid Masood who was born in the county of Kent in south east England. He was known by a number of different names and was known to police for non-terrorist offenses.

"Masood was not the subject of any current investigations and there was no prior intelligence about his intent to mount a terrorist attack," police said in a statement. "However, he was known to police and has a range of previous convictions for assaults, including GBH (grievous bodily harm), possession of offensive weapons and public order offences." He was first convicted in 1983 and his latest offense was in December 2003. He had been living in central England. The car used in Wednesday's attack had been hired in Birmingham.

"The perpetrator of the attacks yesterday in front of the British Parliament in London is an Islamic State soldier and he carried out the operation in response to calls to target citizens of the coalition," the Aamaq statement said.

The IS statement did not name Masood or provide other details. It was not immediately clear whether he was directly connected to the group.

The militant group has encouraged so-called "lone wolf" attacks and has claimed responsibility for past attacks that are not believed to have been planned by its central leadership.

The United Kingdom is a member of the US-led coalition fighting IS in Iraq and Syria.

Attacker was British-born

A total of four people died as a result of Wednesday's attack in London - including the assailant. Around 40 people were injured, with 29 currently being treated in hospitals. Seven of the wounded are in critical condition.

British Prime Minister Theresa May had announced that Masood was British-born but had not given his name. She also told the House of Commons that he had previously been investigated by MI5 intelligence agents over concerns about violent extremism.

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May added that he was not "part of the current intelligence picture" and that there had been no prior intelligence of the plot.

Masood plowed a car into a crowd of pedestrians on London's Westminster Bridge and stabbed a policeman outside the British Parliament on Wednesday. The assailant was shot shortly after stabbing the officer.

Police raids

Police arrested eight people in armed raids carried out in Birmingham and London as part of the investigation into the attack, authorities said earlier on Thursday.

May also revealed the nationalities of those who were wounded in the attack, including: 12 Britons, three French children, four South Koreans, two Romanians, two Greeks, one Irish national, one Polish citizen, one Italian, one American, one Chinese and one German.

The American killed in the attack on the bridge has been named as Kurt W. Cochran from Utah. His wife Melissa was injured at the same time. They were in Europe to celebrate their 25th wedding anniversary.

Police said victims of the attack include 48-year-old Keith Palmer, the policeman who was stabbed, and two members of the public - a woman in her mid-40s and a man in his mid-50s. The attacker is the fourth dead.

Spanish officials said that one of the dead was 43-year-old British citizen Aysha Frade, whose mother was Spanish. She was reportedly en route to pick up her kids from school when the attack occured.

Police reopened Westminster Bridge on Thursday afternoon, around 24-hours after the attack.

Sadiq Khan, the mayor of London, said a candlelight vigil for the victims will be held tonight at 6:00 p.m. GMT (UTC) in Trafalgar Square.

rs, jm/kms (AP, AFP, dpa, Reuters)