The bombing happened at the end of a pop concert by singer Ariana Grande at the arena was attended by thousands of children.
Meanwhile, Greater Manchester Police have made an appeal to the public for information about Mr. Abedi's movements since May 18, when he returned to the United Kingdom from overseas.
LONDON (CNN) - British intelligence service MI5 is launching an internal review into how much it knew about Manchester bomber Salman Abedi prior to last week's deadly attack, British Home Secretary Amber Rudd confirmed on Monday.
As the police operation continued, more questions were being raised about possible security and intelligence blunders surrounding what was known about bomber Salman Abedi.
"The review will look at what was known about Abedi, what decisions were made about the intelligence and what, if anything, could have been done differently", the source said, speaking on condition of anonymity.
Jackson tried to reassure nervous residents of Manchester that the bag does not pose a risk to public safety.
The BBC also said that Abedi had taken part in the armed uprising against Libyan dictator Moamer Kadhafi's regime as a teenager during school holidays.
"Today, we are releasing an image of Abedi carrying a distinctive blue suitcase and an image of a replica of the case".
Abedi could be seen on the night of the massacre, wearing jeans and trainers, a black bodywarmer and a baseball cap, with the straps of the backpack believed to contain the bomb visible on his shoulders. Where did you see him with it during that time?
Greater Manchester Police said they had also executed search warrants at addresses in the Whalley Range area of Manchester and in Chester overnight.
So far, 16 people have been arrested in connection with the investigation, with 14 men remaining in custody for questioning, and two people having been released without charge.
The suspects have not been identified or charged.
That brings the total number of people now detained on United Kingdom soil to 14, all of them men, while Abedi's father and brother have been held in Libya where officials said the two brothers were IS jihadists.
Abedi's elder brother Ismail is among the suspects being held in Britain, and a younger brother and Abedi's father have been detained in Libya.
The security service was apparently warned three times the 23-year-old had extremist views and was a potential threat.
Police are scouring 12,960 hours of closed-circuit TV recordings, and have collected more than 630 pieces of evidence and have searched 21 addresses.
Authorities say Abedi returned to Britain from Libya on May 18, and likely completed assembling his bomb at a rented apartment in central Manchester.
"We believe Abedi was in possession of this case in the days before the attack at Manchester Arena on Monday 22 May".