Abedi was born in Britain to a Libyan family, grew up in Manchester's southern suburbs and attended the local Salford University for a time. British officials, however, have not commented on whether Abedi had links to IS or other extremist groups. A younger brother, 18-year-old Hashim, was also arrested in Tripoli on Tuesday night, a Libyan government spokesperson told the Associated Press.
Police said three men were arrested Wednesday in south Manchester, where a day earlier a 23-year-old man was also arrested and at least two homes were searched.
He said he knew the man from the neighbourhood and the mosque but "in the last 15 years, I haven't seen him in trouble at all".
Before his arrest, the father told the AP that his son was innocent and had been planning a trip to Saudi Arabia for a pilgrimage.
After photos, apparently showing bloodstained fragments of the bomb, appeared in the New York Times, a Whitehall source said: "We are furious".More news: Mike Pence visits Louisiana flood victims he met previous year
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Ramadan Abedi also had said he worked as the administrative manager of the Central Security force in Tripoli.
"This is a very fast moving investigation involving our security services tracking down as rapidly as possible who the accomplices to this terrorist were, as it's unlikely he did this all on his own, and establishing very quickly whether he's part of a network and indeed if further attacks are planned". Abrini visited Manchester in 2015. The two women also lived together in the United Kingdom for years before they returned to Libya.
Officials said all the dead and wounded had been identified.
The sweeping investigation, meanwhile, has caused friction between USA and British security and intelligence officials.
The pictures appeared a day after the bomber's name was briefed to the USA media against the wishes of Greater Manchester Police, and just hours after Home Secretary Amber Rudd issued a plea to United States authorities not to leak material about the atrocity. It was unclear whether Abedi was under surveillance as recently as the attack. Under normal circumstances, he said, Abedi may have been able to travel to the United States because he was from Britain, a visa-waiver country, but he would have been subjected to a background check via the US government's Electronic System for Travel Authorization, or ESTA. Customs and Border Protection has access to a broad array of air travel information through the US government's National Targeting Center.