MI5 has launched two urgent inquiries into how it missed the danger posed by Manchester suicide bomber Salman Abedi, according to reports.

The move comes amid claims that he was repeatedly reported to authorities by teachers and religious leaders concerned that he may become a terrorist.

One review was started last week and aims to identify any glaring errors, The Guardian said.

The other will be more in depth, looking at the process used to assess suspects and asking if different decisions should have been made in Abedi’s case.

Abedi, whose parents come from Libya, is thought to have received terrorist training in the country before returning to the UK just days before detonating the bomb that killed 22 people.

The news comes as 14 men remain in custody being questioned on suspicion of being connected to Abedi’s attack.

The latest – a 23-year-old – was arrested in the early hours of Monday in Shoreham-by-Sea, Sussex, on suspicion of offences contrary to the Terrorism Act.

Earlier on Sunday, Home Secretary Amber Rudd said investigators cannot be entirely sure that Salman Abedi’s terror network has been dismantled – and warned other members of the bomber’s group are potentially still at large.

 Salman Abedi on the night he carried out the attack Police have issued CCTV images of Abedi in a plea for information about his movements in the days before the explosion targeting a sold-out Ariana Grande concert on 22 May.

The NHS says 54 people injured in the attack are still being treated in eight hospitals, and 19 patients are receiving critical care.

During her interview on the BBC’s Andrew Marr Show, Ms Rudd also said Islamic State was trying to weaponise young Britons.

She went on to defend the work of the security services, amid reports that warnings about Abedi were not followed up.

Abedi had been a former subject of interest to MI5, but Ms Rudd said: “The intelligence services are still collecting information about him and about the people around him.

But I would not rush to conclusions, as you seem to be, that they have somehow missed something.

Ms Rudd also revealed that powers to ban suspected jihadis from returning to the UK have been used for the first time.

She refused to say how many times temporary exclusion orders had been used, but confirmed we have started to use them.

The parents of one of the victims has urged the Government to open its eyes to the terror threat facing the UK.

Georgina Callander’s family said the 18-year-old’s life had been cut short by evil, evil men prepared to ruin lives and destroy families.

The statement released through police added: I wish I could say that Georgina is one of the last to die in this way but unless our Government opens its eyes we know we are only another in a long line of parents on a list that continues to grow.