British intelligence will launch a review into how much information it had about the Manchester bomber before his attack last week at an Ariana Grande concert, CNN reports.

Ml5's internal review will focus on finding what information it had on Salman Abedi, who killed 22 people when he blew himself up.

Various reports indicate that the agency had been informed of Abedi's extremist views before the attack.

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The FBI reportedly told Ml5 in January that Abedi was part of an Islamic State in Iraq and Syria cell plotting an attack in the United Kingdom.

"I think it's right that MI5 takes a look to find out what the facts are. We shouldn't rush to make any conclusions at this stage," British Home Secretary Amber Rudd said in an interview with Sky News on Monday.

A 23-year-old was arrested south of London Monday on suspicion of terrorism offenses.

Sixteen arrests have been made as part of the investigation.