The Islamic State has claimed responsibility for the terrorist attack in London that killed three people Wednesday.
The terrorist group published a statement Thursday to its propaganda site, Amaq news agency, calling the assailant "an Islamic State soldier" who carried out the attack outside of British Parliament "in response to calls to target citizens of the coalition," CNN reported.
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It is unclear whether the group had direct ties to the attacker.
Prime Minister Theresa May told members of parliament Thursday the perpetrator was born in Britain and known to authorities, who had investigated him for concerns of religious extremism, but was ultimately regarded a "peripheral figure." Authorities have not yet identified the attacker, who was shot dead by police.
May characterized the attack as "Islamic terrorism" perpetuated by "a perversion of a great faith."
"An act of terrorism tried to silence our democracy, but today we meet as normal," she told Parliament. "We are not afraid and our resolve will never waver in the face of terrorism."
British police said Thursday they had arrested eight people in connection to the attack during raids across Britain on Wednesday night.
Two civilians were killed and several others injured when the attacker plowed a car through crowds on Westminster Bridge. The attacker then fatally stabbed an unarmed police officer outside of Parliament before armed officers shot him dead. Authorities believe the assailant acted alone.
The London attack arrived on the one-year anniversary of the deadly ISIS bombings in Brussels that killed 32 people.
The United Kingdom's threat level remains severe, meaning an attack is highly likely. The assessment remains unchanged after the attack in London Wednesday.