In Manchester, northwest England, feelings were still raw following Abedi's attack on a concert by United States pop star Ariana Grande-especially so as the bomber was born in the city.
The number of arrests in the United Kingdom ticked up to eight yesterday as Britain remains on high alert for a follow-up attack.
The Arndale Centre is a short walk from the Manchester Arena, the scene of the attack which killed 22 people on Monday night (local time).
The man was arrested in the Moss Side area.
It comes after Britain raised the threat level to critical - the highest in a decade - and deployed armed soldiers to support police.
University dropout Abedi, 22, grew up in a Libyan family that reportedly fled to Manchester to escape the now-fallen regime of Libyan dictator Moamer Kadhafi.
The incident, which came as concertgoers were preparing to leave an Ariana Grande concert in the city's heart, took the lives of at least 22 people, including several children.
Two community leaders also reported Abedi over his extremist and radical beliefs.
"The alleged leaks coming out of government agencies are deeply troubling", Trump said in a statement released after he arrived in Brussels for a North Atlantic Treaty Organisation summit, also attended by May.
Authorities have found more evidence - including leaked photos of the remnants of the bomb itself - that suggest the attack was the work of a terror network. Abedi was in Libya for three weeks and returned days before his attack, US military officials assigned to US Africa Command told CNN.
British police are irritated that information shared with USA officials has leaked to US media, which reported Abedi's name before police confirmed it.
U.S. congressman Mike McCaul, Republican chairman of the House Homeland Security Committee, said the bomb was of a "level of sophistication" that might indicate its maker had foreign training.
The official said Turkey had not received any information from foreign intelligence services about Abedi, so he did not raise any red flags.
As the nation mourns, Queen Elizabeth II visited victims and hospital personnel at the Royal Manchester Children's Hospital today.
Her only direct comment since the attack has been a social media posting shortly afterwards in which she said she felt "broken" and "so so sorry".