Salman Abedi was reported to authorities for his extremist views, yet he managed to walk into Manchester Arena and detonate a suicide bomb, killing 22 people.

The British-born son of Libyan parents, he was banned from a mosque in the city, after criticising an Imam for "talking bollocks" during a sermon criticising the Islamic State (IS) terror group.

A number of people who knew him, and even family members, had reportedly warned authorities he was developing radical views - including, the BBC said, that being a suicide bomber was ok - prompting concerns that signs of the threat he posed were missed.

The 22-year-old's father Ramadan and brother Hashim have been detained in Libya and another brother, Ismail, was arrested in Manchester on Tuesday.

In an interview before his arrest Ramadan Abedi rejected claims he was a member of the Libyan Islamic Fighting Group, but added that he supports the organisation, which is banned in the UK.

In the translated interview, shown on BBC, he said: "I condemn anyone who says I belong to Libyan Islamic Fighting Group.

"I commend them but I don't belong to any organisation."

While Abedi was born and raised in Manchester, his parents had arrived in the UK having fled the Gaddafi regime in Libya the early 1990s.

Protesting his son's innocence with regard to the Manchester Arena explosion, Ramadan Abedi added: "I'm sure that Salman didn't carry out such an act."

The French interior minister said Abedi had "most likely" been in Syria, another claim his father dismissed, saying he had checked his son's passports.

While Mr Abedi said his son had seemed "normal" when he spoke to him five days before the atrocity, Jamal Zubia, a member of the large Libyan community in Manchester, told the Times the parents were so concerned about their son's apparent descent into extremism that they took his passport.

He said: "The father had all the passports with him and was holding them."

But Abedi convinced them to return it, claiming he wanted to make a pilgrimage to Mecca, Mr Zubia said.

It is reported he in fact came back to the UK, via Germany, from Turkey four days before the bombing.

A German magazine reported that he came through Duesseldorf, and said he had not been on any international watch list.

Akram Ramadan, 49, part of the close-knit Libyan community in south Manchester, said Hashim, who he described as "the little boy", had lived in Germany.

Mr Ramadan, who lived in the flat above Ismail, said of the incident when Abedi was banned from Didsbury Mosque: "There was a sermon about anti-Daesh (IS) and he stood up and started calling the Imam - 'You are talking bollocks.'

"And he gave a good stare, a threatening stare into the Imam's eyes.

"He was banned."

Police raided a city centre flat in Manchester on Wednesday, which a nearby bar owner said they told him they believe Abedi had been in before he carried out the bombing.

Just 15 minutes before he blew himself up in Manchester Arena, Abedi called his mother and brother, a spokesman for the Libyan government told the Times.

They claimed Hashim admitted, under interrogation, that he was aware of his brother's plans.