The Islamic State (Isis) has claimed responsibility for the attack, which left four people dead and 29 injured in London.
According to Amaq News Agency, ISIS official press service, the attacker was a “soldier of the caliphate”.
“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,” said the statement by Amaq.
Meanwhile, UK Prime Minister Theresa May said on Thursday that the man responsible for the attack was born in Britain and known to the intelligence services.
“What I can confirm is that the man was British-born and that some years ago he was once investigated by MI5 in relation to concerns about violent extremism,” May told members of Parliament.
“He was a peripheral figure. The case is historic, he was not part of the current intelligence picture. When operational considerations allow, he will be publicly identified.”
The UK police say they have arrested seven people at six locations in London and Birmingham in the investigation into the attack.