(independent) -- Dressed unremarkably, the 22-year-old carries a rucksack and partly obscures his face with a baseball cap

 Terrorist Salman Abedi cuts an unremarkable figure in jeans and a dark, padded jacket in his final moments before he slaughtered 22 concert-goers and seriously injured dozens more on Monday night.

He also appears to be wearing a backpack with black straps. It is believed he may have used a rucksack to carry the shrapnel bomb that tore through crowds exiting the Manchester Arena after the Ariana Grande concert.

Abedi's features are partly obscured from the CCTV camera by a baseball cap and glasses.

The images are the first to show what the 22-year-old looked like when he carried out the deadliest terror attack Britain has seen since the 7/7 bombs of 2007, in which 52 people were slaughtered.

Greater Manchester Police has not revealed where the footage was taken or at what time.

Abedi is believed to have put the final touches to his bomb in a city centre flat before he travelled to the concert which had an audience of 21,000 mainly young people and children.

Police, who have 11 people in custody in connection with the atrocity, said they had built up a "detailed picture" of Abedi’s movements since he returned to British shores on 18 May, reportedly from his family's native Libya where it is believed he may have received training from terrorists.

They made a further appeal to the public for information about Abedi's activity between the arrival in the UK and his suicide attack.

The force said in a statement: "We immediately established full command and control of the incident and within an hour of the attack taking place a specialist counter terrorism control room had been established with a first priority of identifying the attacker.

"Specialist counter terrorist forensic teams were sent to try and identify the attacker and within two hours his identity was known."

The investigation has so far involved around 1,000 officers, as a huge operation was launched to suppress any further terror threats posed by Abedi's potential network.

The UK was put on “critical alert” following the attack but the threat has now been downgraded to “severe” following the arrests.