Updated

The Islamic State terrorist group claimed responsibility Monday for the knife attack in London over the weekend that left three people injured.

Sudesh Amman, 20, strapped on a fake bomb and stabbed two people on a busy London street Sunday before being shot and killed by police. Investigators say a third person suffered injuries believed to have been caused by broken glass when responding officers opened fire.

“The perpetrator of the attack in Streatham district in south London yesterday is a fighter of Islamic State, and carried out the attack in response to calls to attack the citizens of coalition countries,” a statement posted by ISIS’ Amaq news agency read, according to Reuters.

Fox News has confirmed the claim of responsibility.

A police forensic officer looks around near the scene after a stabbing incident in London on Sunday

A police forensic officer looks around near the scene after a stabbing incident in London on Sunday (AP)

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Amman had been recently released from prison. Metropolitan Police Deputy Assistant Commissioner Lucy D’Orsi said he served time after being convicted of publishing graphic terrorist videos online and stockpiling instructions on bomb-making and knife attacks.

Officers had been trailing Amman at the time of Sunday's attack, D'Orsi said, but were unable to head off the bloodshed in the commercial and residential south London neighborhood of Streatham, where Amman struck outside a major pharmacy.

The British government said Monday it will introduce emergency legislation to stop people convicted of terror crimes being released after serving half their sentences, following Amman’s attack and a similar stabbing spree late last year.

None of the victims in Amman’s attack suffered life-threatening injuries, while the Nov. 29 stabbings near London Bridge -- which were carried out by another man who also had served prison time for terrorism offenses -- left two dead.

“Yesterday’s appalling incident makes the case plainly for immediate action,” Justice Secretary Robert Buckland told lawmakers. “We will therefore introduce emergency legislation to put an end to terrorist offenders getting released automatically having served half of their sentence with no check or review.”

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Police in London say Sudesh Amman strapped on a fake bomb and stabbed two people before being shot to death by responding officers. He was recently released from prison, where he was serving time for terrorism offenses. (AP/Metropolitan Police)

Police in London say Sudesh Amman strapped on a fake bomb and stabbed two people before being shot to death by responding officers. He was recently released from prison, where he was serving time for terrorism offenses. (AP/Metropolitan Police)

He said terror convicts would have to serve at least two-thirds of their sentences, and wouldn't be freed before the end of their full terms unless the Parole Board agreed.

Buckland said the new rules would apply to people who are currently serving sentences as well as those sentenced in the future. More than 70 people convicted of terrorism offenses have been released in Britain after serving time in prison and more than 200 others are currently imprisoned.

“This is a liberal country, it is a tolerant country,'' Prime Minister Boris Johnson said. “But I think the idea of automatic early release for people who obviously continue to pose a threat to the public has come to the end of its useful life.”

Johnson added that de-radicalizing people is a “very, very difficult thing to do” and that he was concerned about the way convicted terrorists in prison are handled.

“Do you detain them en bloc, in one group, and try to keep them together because that avoids them, as it were, infecting or passing the virus of their beliefs to others in jails, or do you disperse them and try to stop them reinfecting each other?” he said.

Amman was sentenced to three years and four months. Taking into account time served after his arrest, he was freed a week ago, Buckland said.

Police on Monday continued to search a hostel near the attack site where Amman had been staying, and also raided another property outside of London.

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London Mayor Sadiq Khan said Sunday’s attack was clearly foreseeable in the wake of the London Bridge murders.

“One of the questions I've got for the government is what are we doing about those 70-odd people who have been released from prison?” he asked.

Fox News' Gillian Turner and the Associated Press contributed to this report.