U.S. intelligence leak 'undermines' United Kingdom bomb investigation

British police arrested a seventh person on Wednesday in connection with the massacre at a Manchester pop concert that left 22 people dead.

May also said Thursday that progress is being made in the Manchester bombing investigation noted the national threat level remains critical - meaning another attack may be imminent.

Abedi's younger brother Hashem has also been arrested in Libya, on suspicion of having links to ISIS, who claimed responsibility for Monday night's atrocity.

A British official said Manchester police have decided not to share further information on the probe with the United States due to leaks blamed on USA officials. Britain's interior minister said earlier that he had recently returned from Libya and had likely not acted alone.

A spokesperson for the Libyan authorities told BBC that, "His brother felt there was something going on there in Manchester and he thought his brother would do something like bombing or attack".

Police have arrested and detained 11 suspects so far.

British police and security services were also upset that Abedi's name was apparently leaked by USA officials and published while police in Britain were withholding his name - and while raids were underway in Manchester and in Libya, where the bomber's father lives.

Now, he is the administrative manager of the Central Security force in Tripoli.

Information in so-called "IS Files" - a huge cache of documents obtained by "Sky News" shows how an ISIS fighter called Raphael Hostey, from Moss Side in the south of Manchester, sponsored hundreds of terror recruits.

Abedi and Hostey reportedly hung around on the same estates and worshipped in the same Didsbury mosque, before they became disaffected with life in the West.

The Greater Manchester Health and Social Care Partnership said on Wednesday that as many as 119 people had been injured in the attack, 64 of whom remain hospitalised, 20 of them critically.

Others, including parents, were waiting in the foyer to pick up family and friends when the bomb went off. Grande has suspended her world tour in the wake of the attack, her representative said.

"Manchester Evening News readers have been asking how they can help, so we have started this fund to help support the families in the aftermath of the attack", the description of the campaign on fundraising site JustGiving says.

The 22 victims in Manchester included an eight-year-old girl, several teenage girls, a 28-year-old man and a Polish couple who had come to collect their daughters.

Queen Elizabeth II visited Royal Manchester Children's Hospital on Thursday to talk to some of the concert blast victims.