Updated May 25, 2017 23:16:09

A Muslim community leader in Manchester claims authorities missed warning signs about suspected bomber Salman Abedi.

Mohammed Shafiq told the ABC's 7.30 a number of locals had reported Abedi to authorities in recent years.

Here is what we know so far about the man suspected of killing 22 people with a nail bomb in Manchester at an Ariana Grande concert.

"We know about two years ago a community activist here in Manchester understood that Salman Abedi was expressing viewpoints which were extremist and he was glorifying suicide bombing and supporting Islamic State, and he reported that to the counter-terrorism unit through the hotline on two separate occasions," Mr Shafiq said.

"As well as that, a number of family members were also reporting the radicalisation and the extremism that Salman possessed and reported that to the authorities.

"So he was on the radar of intelligence agencies and there are serious questions for our intelligence agencies and police in this country to answer about what they knew, what they did with that information and whether they followed it through."

Britain's Home Secretary Amber Rudd has previously said Abedi had been known to security forces "up to a point".

Abedi, a 22-year-old British citizen born to Libyan parents, died in the attack, which targeted fans leaving a concert by US pop star Ariana Grande.

Twenty-two people, mainly young fans, were killed, with dozens more injured.

Photo: Ramadan Abedi denied his son's involvement in the attack. (AP)

UK police have arrested eight people in the aftermath of the bombing, with Ms Rudd saying Abedi "likely" did not act alone.

Abedi's father and brother were also arrested by authorities in Libya.

Libyan counter-terrorist officers in Tripoli arrested Salman Abedi's brother, 18-year-old Hashim Abedi, and said the teenager had confessed that both he and his brother were a part of the Islamic State (IS) group.

But the father, Ramadan Abedi, denied his son's involvement in an interview with before being arrested, saying they did not "believe in killing innocents" and he believed "hidden hands" were behind the attack.

Photo: Hashim Abedi, the younger brother of the Manchester bomber, has been arrested. (Facebook: Yousef Hannaa)

'People opened their doors and hearts'

Asked if there had been any backlash against the Muslim community in Manchester since the bombing, Mr Shafiq said he was proud of the way people in the city had come together.

"Just after the explosion taxi drivers, predominantly Muslim taxi drivers, were picking up people and dropping them off to make sure they got home safely. One taxi driver dropped someone home 60km away," he said.

"People opened their doors and hearts and here in downtown Manchester, people are not allowing this to divide us. We are going to stand determined, resolutely united against terrorism. We are one town, one city.

"We are proud to show the world how you react to a terrorist atrocity."

Photo: Police forensic investigators search the property of Salman Abedi. (AP: Danny Lawson)

Topics: terrorism, united-kingdom

First posted May 25, 2017 20:48:19