Tripoli, Libya: Libya has arrested a brother and the father of the man suspected of carrying out the bombing in the British city of Manchester, a relative and security sources said on Wednesday.

The family source, asking not to be identified, said intelligence services had arrested Hashem Abedi, who like his older brother Salman was born in Britain, on Tuesday.

One of the forces that supports Libya’s UN-backed unity government posted a picture on its Facebook page of Hashem Abedi after detaining him.

‘The father, Ramadan Abedi, has also just been arrested,’ said Ahmed bin Salem, a spokesman for the Deterrence Force, which acts as Government of National Accord’s police.

He said the brother was aware of Salman Abedi’s attack plan and that the two brothers were both members of the Islamic State group.

The Monday night bombing at a pop concert killed 22 people, including children as young as eight.

IS claimed responsibility for the attack on Tuesday through its social media channels, saying ‘one of the caliphate’s soldiers placed bombs among the crowds’.

Hashem had been ‘under surveillance for a month and a half’ and ‘investigation teams supplied intelligence that he was planning a terrorist attack in the capital Tripoli’, the Deterrence Force said on its Facebook page.

He was arrested on Tuesday evening as he received 4,500 Libyan dinars (around 650 dollars) from his brother Salman, it said, without providing further details.

The relative said Salman had travelled to Manchester from Libya four days before the bombing.

‘His father wanted his son to stay in Libya but Salman insisted on going to Manchester.’

Salman Abedi, 22, was born in Manchester to Libyan parents who reportedly fled the regime of slain dictator Moamer Kadhafi.

Britain’s interior minister, Amber Rudd, confirmed on Wednesday that Salman was known to intelligence services and that it was ‘likely’ he was not working alone.

Her French counterpart Gerard Collomb said he had become radicalised after a trip to Libya and probably Syria, according to information received from UK intelligence services.

‘In any case, the links with Daesh are proven,’ Collomb said, using another term for IS.