Manchester attack: 'Trainee pilot' arrested as search spreads across Britain

People look at flowers and tributes left in St Ann's Square in Manchester, a week after the Manchester Arena terror attack. Photo / AP

A "trainee pilot" has been arrested as the investigation into the terror network behind Salman Abedi spreads across Britain.

The 23-year-old, understood to be Libyan, was arrested at a property in Shoreham-by-Sea, Sussex, more than 420km from the Manchester Arena where Abedi detonated a suicide bomb a week ago killing 22 people.

Neighbours said that they were shocked that the police activity had reached their doorstep, the Daily Telegraph reports.

Violet Mainda, the Kenyan-born owner of Violet's Hairdresser's beneath the flat, said: "He was a young Libyan guy who was always very jovial and nice.

"He said he was training to be a pilot at Shoreham Airfield and he had just completed doing that. I am really, really shocked by this. I can't believe he had been arrested.

"He had a few friends and a girlfriend and always seemed very nice. I don't know if he worked, I think he just studied to be a pilot. He said he was studying to become a pilot at Shoreham."

Armed officers also swooped on sites across Manchester in a flurry of raids and arrests over the weekend as they worked to stamp out any lingering threat from co-conspirators to the massacre.

The Sussex arrest brings the number of people in custody in relation to the the attack to 14.

Shoreham Airfield said that they did not have anyone available to comment.

Police are warning people not to approach a blue suitcase Salman Abedi was seen carrying days before the deadly Manchester bombing.

The public are being asked to contact police immediately if they see the piece of luggage.

It comes as CCTV footage obtained by the BBC also shows Abedi shopping a day before the attack.

Salman Abedi pictured on CCTV in Manchester with a suitcase. Photo / AP

He is believed to have bought food and cleaning products, including almonds, tuna, scouring pads and air fresheners, at a convenience store near Granby Road, which is where he assembled the bomb.

Greater Manchester Police have released an image of the suicide bomber with the hip-high case in the city centre on May 22.

Detective Chief Superintendent Russ Jackson, from the North West Counter Terrorism Unit, said: "We believe Abedi was in possession of this case in the days before the attack at Manchester Arena.

"I want to stress that this is a different item than the one he used in the attack."

He added: "We have no reason to believe the case and its contents contain anything dangerous, but would ask people to be cautious."

Jackson continued: "The public should not approach the case if they see it but contact police immediately."

As well as the CCTV image of Abedi, detectives have released a picture of a replica case, as they continue to piece together the terrorist's movements in the lead-up to the attack.