British police and security services are also upset that the name of British bomber Salman Abedi was apparently leaked by USA officials and published while police in Britain were withholding the name for operational security.
Speaking at his home in Tripoli, Ramadan Abedi said: 'I was really shocked when I saw the news, I still don't believe it.
A spokesman for the local counter-terrorism force said younger brother Hashem Abedi was arrested on suspicion of links with the Islamic State and was suspected of planning to carry out an attack in Tripoli.
Officials are probing how often Abedi had traveled to Libya, which has seen an eruption of armed Islamist groups since dictator Moammar Kadaffi was overthrown and killed in 2011.
Home Secretary Amber Rudd complained the leaks could cost police "the element of surprise" in their bid to prevent future attacks. Her French counterpart Gerard Collomb said he had links with Islamic State and had probably visited Syria as well.
A European security official said "having a US leak when the situation has developed in the U.K.is nothing new".
The victims identified, so far, include 8-year-old Saffie Rose Roussos.
Britain's official terror threat level was raised on Tuesday to "critical", which is the highest level and means that an attack could be imminent.
In the hours that follow tragedy - such as Monday night's terrorist attack during an Ariana Grande concert in Manchester that claimed the lives of 22 people and injured 59 concertgoers - there are certain members of society who wish to politicise the hurt and sadness for their own agenda. An initial deployment of 984 had been ordered, first in London and then elsewhere.
Soldiers were replacing armed police on Wednesday at sites including Buckingham Palace, 10 Downing Street and Parliament.
Hopkins said the leaks of details of the investigation to US media, which included forensic photographs of the bomb site published by the New York Times, had been hurtful to the families of the victims.
She also complained about USA officials leaking sensitive information about Abedi to the press, saying that could hinder Britain's security services and police.
He said: 'I can confirm that the man suspected of carrying out last night's atrocity has been named as 22-year-old Salman Abedi.
British police are rushing to uncover the network thought to have helped Manchester Arena bomber Salman Abedi in the attack on the Ariana Grande concert. She has also called out the army which has started taking over from police in guarding key installations and crowded events.
The act prohibits them from sharing sensitive information regarding national security but also prevents them from sharing security information involving other countries.
ISIS claimed Monday's attack, saying on its Telegram channel Tuesday that a "soldier of the caliphate" was able to "plant explosive devices" at the arena, according to a USA counterterrorism source.
"We are sure our fans will understand this decision", the team said, adding that the parade would have diverted police from the bombing investigation.
Rudd said Britain's increased official threat level would remain at "critical" as the investigation proceeds and wouldn't be lowered until security services are convinced there is no active plot in place.
In addition to those killed, 116 people have received medical treatment at Manchester hospitals for wounds from the blast.