ISIS claims responsibility for London terror attack; PM Theresa May says British-born suspect was once investigated by MI5

ISIS has claimed responsibility for the terror attack in London on Wednesday. The terror group's Amaq news agency says it is behind the suspected lone wolf attack.

On Thursday, British Prime Minister Theresa May had also confirmed that the London terror attacker was born in Britain and was previously investigated by the secret service agency MI5.

At least two people were killed, including a police man, and over 40 were injured during an attack outside the UK Parliament on Wednesday. A man "in his 40s with eight-inch long knife" clad in black clothes was shot dead by police  after he "mowed down" at least a dozen pedestrians by a car and stabbed a policeman close to Britain's Houses of Parliament in London.

Read: 7 arrested over links with 'depraved' attack; second victim identified as Spanish teacher

The police have said they were treating the incident as an act of terrorism.

PM May in a speech on Thursday said the country will "never waver in the face of terrorism."

"I can confirm police have searched six addresses and made eight arrests in Birmingham and London. It is still believed this attacker acted alone and police have no reason to believe there are imminent further attacks on the public. His identity is known to the police and MI5," May in a statement said.

"When operational considerations allow he will be publicly identified. What I can confirm is the man was British born and that some years ago he was once investigated by MI5 in relation to concerns about violent extremism. He was a peripheral figure. The case is historic. He is not part of the current intelligence picture," the Prime Minister added.

12 Britons and people from at least 10 nationalities, including three French children, two Romanians, four South Koreans, one German, one Pole, one Irish, one Chinese, one Italian, one American and two Greeks were injured in the attack.

The two deceased include a 48-year-old police officer, Pc Keith Palmer, who was killed inside the gate of UK Parliament as the attacker stabbed him with a knife. The other victim was identified as a 43-year-old Spanish teacher Aysha Frade who was on her way to pick up her two children from school.

A total of eight arrests have been made in connection with the incident so far.

British Prime Minister Theresa May