The British parliament's Intelligence Security Committee on Thursday published a damning report on the 2017 Manchester Arena terror attack.

The report said British security services failed to adequately deal with 22-year-old perpetrator Salman Abedi's case and, as such, missed several opportunities to possibly prevent the attack.

It also noted that security services did not heed suggestions provided in previous reports on terror attacks in the UK.

"While it impossible to say whether these would have prevented the devastating attack on May 22, we have concluded that, as a result of the failings, potential opportunities to prevent it were missed," said British lawmaker Dominic Grieve, who chairs the committee.

Twenty-two people were killed exiting a concert by American singer Ariana Grande at the Manchester Arena when Abedi, a British citizen born to Libyan parents, detonated shrapnel-laden explosives.

Read more: Opinion: The normality of terrorism

Shortcomings

Security services, including the UK's domestic intelligence agency, MI5, and London's Metropolitan Police counterterrorism unit, had flagged Abedi as early as 2010. MI5 also briefly investigated him in 2014, but did not recommend his case to a counterextremism program.

The report singled out both security services for not following up with Abedi after he visited an extremist contact in prison. The failure to monitor Abedi after the prison visit allowed him to "return undetected" to Britain after a brief trip to Libya, it added.

The case was reminiscent of German security service's treatment of Anis Amri, a Tunisian national and failed asylum seeker who drove a lorry into a Christmas market crowd, killing 12 people and injuring dozens more.

Amri managed to elude German law enforcement despite once being described as a security risk. Although he told a federal police informant that he "wanted to do something big" and could acquire an AK-47 assault rifle to commit an attack, a brief investigation resulted in him being deemed an "unlikely" threat.

Read more: Madrid to Manchester to Barcelona: A chronology of terror in Europe

'An attack is highly likely'

Interior Minister Sajid Javid thanked the committee for the report, noting that "we will review and formally respond to it in due course."

"Following the attacks, the government, police and MI5 undertook a series of rigorous reviews to ensure we are all doing everything we can to tackle the evolving threat of terrorism," said Javid.

The UK's perceived terror threat level is currently defined as "severe," meaning "an attack is highly likely." It hasn't been lower than severe since 2014.

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ls/msh (AP, Reuters, AFP)