US news broadcaster CNN has quoted US intelligence sources as saying Manchester suicide bomber Salman Abedi likely received Islamic State training, in a report published the same day Donald Trump apologised for the leaking of UK information.

British Prime Minister Theresa May earlier vowed to confront Mr Trump over the leaks, which have potentially hampered investigations into the Manchester bombing that killed 22 people and injured more than 116.

UK police temporarily stopped sharing information about the bombing with the US after British officials were reportedly furious when photos showing remnants of the bomb and shrapnel from the attack appeared in The New York Times on Wednesday morning (US time).

The sharing of information resumed Friday morning after UK authorities accepted fresh assurances of confidentiality from the US.

The NYT story came after Abedi’s identity was also leaked to US media within hours of the attack.

Abedi blew himself up outside Manchester Arena after an Ariana Grande concert packed with children on Monday night local time, killing 22 people and injuring 116.

UK police have arrested eight people suspected of being involved in the bombing, while Abedi’s father and younger brother were detained in Libya.

One of the people arrested in the UK is believed to be Abedi’s older brother.

Mr Trump, in Brussels for a NATO summit along with Mrs May, said: “These leaks have been going on for a long time.”

He said he would ask the US Department of Justice to launch a review into the leaks and “if appropriate, the culprit should be prosecuted.”

“There is no relationship we cherish more than the special relationship between the US and the UK,” the President said.

Greater Manchester Chief Constable Ian Hopkins said Thursday night the arrests made in the UK since the bombing are “significant”.

“Initial searches of premises have revealed items that we believe are very important to the investigation,” he said.

He previously warned that police were investigating a terror “network”.

Police are still hunting for a possible bomb-maker amid theories that Abedi was acting only as a “mule” to carry the improvised explosive.

UK media have broadcast photos of what is believed to be Abedi walking through the city centre wearing the backpack he reportedly used to carry the explosives.

This image reportedly shows Abedi carrying the backpack he allegedly used in the bombing. Photo: Sky News

Sky News aired two screengrabs of security camera footage, reporting that British police believed they showed Abedi walking on Friday in Manchester’s Arndale shopping centre which is close to the Manchester Arena.

The man seen in the images is carrying a blue backpack on his back, which police believed was used in the bombing.

British police believe Abedi withdrew 250 British pounds ($430) from an ATM before he went shopping in the centre around 7pm (local time), Sky reported.

Abedi was known to authorities

British media outlets have reported that Abedi’s potential for radicalisation had been reported to counter-terror agencies as far back as five years ago.

The Independent newspaper has reported that two people who knew Abedi while at college had alerted the anti-terror hotline after he had told them “being a suicide bomber was okay”.

The paper reported that the calls were thought to have been made five years ago, soon after Abedi left school.

The Daily Telegraph also reported that chief executive of the Ramadhan Foundation, Mohammed Shafiq, had reported Abedi two years ago “because he thought he was involved in extremism and terrorism”.

“People in the community expressed concerns about the way this man was behaving and reported it in the right way using the right channels,” Mr Shafiq told the paper.

“They did not hear anything since.”

Abedi had also been banned from his local mosque and been placed on a “watch list” by authorities after his extremist views emerged, The Independent reported.

Injury toll rises

A minute’s silence was held in memory of the victims at 11am around the country, as The Queen flew to Manchester to visit a hospital caring for many of the survivors.

The Queen meets some of the survivors. Photo: AAP

The Queen met some of the injured at Royal Manchester Children’s Hospital, and mingled with staff who had toiled through the night after the attack to save the victims’ lives.

The National Health Service confirmed the injury toll had risen to 116, with 75 admitted to hospital and 23 under close care.

– with agencies