Akran Ramadan, who is part of the Libyan community in south Manchester, said he understood Abedi had been placed on a "watch list" after the mosque banned him and reported him to the authorities for his extremist views.
The allegations clashed with what Abedi's father said a day earlier in an interview with the AP, in which he said "We don't believe in killing innocents".
"When that trust is breached it undermines these relationships and threatens our investigations and the confidence of victims, witnesses and their families". The statement went on to say the damage is greater when information is leaked in the middle of a major investigation.
The decision to stop sharing police information with United States agencies was an extraordinary step as Britain sees the USA as its closest ally on security and intelligence.
Police have said it is "very clear" there is a "terror network" at work that is likely to have helped the Manchester-born attacker.More news: Trump tells North Atlantic Treaty Organisation leaders to spend more for defense
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On Thursday morning, the BBC reported that the Greater Manchester Police will no longer be sharing information on the bombing inquiry with their American counterparts.
His Libyan father, Ramadan Abedi, who lives in Tripoli, said his son Salman was there six weeks ago. According to ABC, at least eight other suspects allegedly connected to the attack have been arrested.
A security source told Sky News: "MI5 are working on 500 active investigations involving some 3,000 subjects of interest at any one time". Queen Elizabeth II visited Royal Manchester Children's Hospital, telling 14-year-old Evie Mills and her parents: "It's awful".
She told Evie Mills (14) and her parents: "It's awful".
Before carrying out the deadly attack at Manchester Arena, Abedi had joined Manchester's huge student population.
The 23-year-old, who suspended her tour and returned to her Florida home after the tragedy, said she planned a concert as "an expression of love for Manchester".
British police and security services were also upset that Mr Abedi's name was apparently leaked by U.S. officials and published while British police were withholding it - and while raids were underway in Manchester and in Libya, where the bomber's father lives.
Scooter Braun, Grande's manager, wrote a series of tweets telling his 4.1 million followers not let terrorism win after a suicide bombing killed 22 people, including young children, and injured dozens Monday. Authorities have said they believe the plot was months in the making.