Police have now arrested a total of nine people in relation to Monday’s Manchester suicide bombing outside an Ariana Grande concert that left 22 people dead and at least 64 injured.

The father and younger brother of Manchester suicide bomber, Salman Abedi, were detained in Libya as British police revealed they are now facing a terror “network”.

Abedi’s younger brother, Hashem, 20, was arrested in the Libyan capital Tripoli on Thursday morning (AEST) over suspected links with Islamic State, according to Reuters.

The bomber’s older brother, Ismael, was detained in Manchester on Wednesday.

The men’s father, Ramadan Abedi, was also detained in Tripoli a day after telling The Associated Press: “We don’t believe in killing innocents”.

The Abedi family arrests came as raids in the UK led to seven arrests, including one woman.

Abedi detonated an improvised explosive filled with nails and other shrapnel outside Manchester Arena on Monday night (UK time).

Of the 64 people injured, 20 are in a critical condition and 12 of them are children.

“I think it’s very clear that this is a network that we are investigating,” Greater Manchester Police Chief Constable Ian Hopkins told a media conference on Wednesday.

“And as I’ve said, it continues at a pace. There’s extensive investigations going on and activity taking place across Greater Manchester as we speak.”

One of the main focuses of the investigation is identifying and apprehending the bomb-maker behind the Manchester Arena device.

Hashem Abedi after his arrest in Tripoli.

Almost 1000 soldiers were deployed on Wednesday (UK time) on Britain’s streets to support police after the Manchester suicide bombing, with the nation on the highest terror alert of “critical” amid fears another attack is “imminent”.

Six of the UK arrests have been carried out in the Manchester area, with the seventh resulting from a raid in Nuneaton, Warwickshire.

Amid warnings that another terror attack could be imminent, British Home Secretary Amber Rudd said a total of up to 4000 soldiers could be deployed throughout Britain to free up police to carry out patrols and investigation work.

Armed troops are understood to be assuming responsibility for guarding high-profile buildings and embassies, with many on Wednesday taking up position at Buckingham Palace, Parliament and Downing Street as part of an operation dubbed Operation Temperer.

The BBC on Wednesday evening (AEST) reported a security correspondent as saying that Abedi had acted as a “mule”, meaning he was unlikely to have designed and built the bomb himself, but merely been the carrier.

Officials have been examining Abedi’s trips to Libya as they work to piece together his allegiances and foil any new potential threats. 

Ms Rudd said Abedi had been known to security forces “up to a point”, while French authorities told British counterparts that Abedi had also probably travelled to Syria.

Jon Rouse, chief officer for health and social care services in the Greater Manchester area, described the injuries sustained by the wounded bombing survivors as “highly traumatic”.

“There is damage to major organs, major injuries in terms of limbs and some of these individuals are going to need very long term care and support,” he told Sky News.

The Manchester attack was the deadliest in Britain since July 2005, when four British Islamic suicide bombers killed 52 people in coordinated attacks on London’s transport network.

Salman Abedi, 22, also travelled to Syria, according to French intelligence sources. Photo: Supplied

‘A face of hate’

US security sources, citing British intelligence officials, said Abedi was born in Manchester in 1994 to parents of Libyan origin.

Born and raised in Manchester, Abedi grew up in a Muslim household, and studied business at Salford University until he dropped out and went to work in a local bakery.

Neighbours described an abrasive, tall, skinny young man who was little known in the neighbourhood, and often seen in traditional Islamic clothing.

Abedi previously lived with his mother, Samia Tabbal and father Ramadan, who preached at a local mosque. 

A family friend, who asked not to be named, said they were known to the city’s Libyan community and described Abedi as “normal”.

“He was always friendly, nothing to suggest (he was violent). He was normal, to be honest,” he said.

Abedi also attended the Manchester Islamic Centre where he reportedly caught the attention of one imam whom he stared down during a sermon denouncing terrorism.

“Salman showed me a face of hate after that sermon,” Mohammed Saeed told The Guardian of the 2015 encounter.

The victims

The identities of the victims are also gradually becoming known.

The victims named so far are:

Saffie Roussos (aged eight), Georgina Callander (18), Olivia Campbell (15), Megan Hurley (age unknown), Chloe Rutherford (17), Liam Curry (19), Michelle Kiss (45), Cheshire female police officer (unnamed), Martyn Hett (29), Kelly Brewster (32), Angelika Klis (40), Marcin Klis (42), John Atkinson (26), Alison Howe (45), Lisa Lees (47), Nell Jones (14), Jane Tweddle (51), Sorrell Leczkowski (14) and Wendy Fawell (age unknown).

Eilidh MacLeod (14), Courtney Boyle (19) and Philip Tron (32) remain among the missing.

– with agencies