People observe a minute's silence to honor the victims of the Manchester Arena attack at St. Anne's Square in Manchester, Britain, May 25, 2017.
Prime Minister Theresa May said developments in the investigation into the bombing meant intelligence experts had chose to lower the threat level from its highest rating "critical", meaning an attack could be imminent, to "severe".
Since the attack, there has been a rise in hate crimes, with Greater Manchester Police saying offences have doubled since Monday night.
Asked during an interview on BBC television whether some of the group were still at large, Rudd said: "Potentially". In response, the threat level had been raised to the highest category a day later. Khan urged Londoners to remain vigilant, he said via Facebook.
However, police needed any information the public might have about his movements from May 18 when he returned to Britain.
British-Libyan Abedi caused carnage by setting off a bomb packed with screws and ball-bearings, leaving more than 100 people injured.
"We thought he must have been a drug dealer or doing witchcraft", Mr El-Hudarey told the broadcaster.Two more men have been arrested overnight in connection with the Manchester bombing.London Mayor Sadiq Khan said enhanced security plans would remain in place in the capital this weekend despite the downgrading of the national threat level.
Britain's senior counter-terrorism officer, Mark Rowley, told Sky News: "They are very significant, these arrests". "There is still much more to do".
"There will be more arrests and there will be more searches", he said.More news: United Kingdom terror threat level lowered
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Eleven people are now being held in connection with the Manchester bombing, which killed 22 people at the Ariana Grande concert on Monday night.
Armed police officers and soldiers were deployed at soccer matches, concerts and other big events.
About 3,000 of the 23,000 jihadists are judged to pose a threat, the report said.
There was a highly-visible police presence as runners gathered on the start line for the Manchester run at 9.00 am.
"A visible, united, police presence making sure everyone has a good time at tonight's gig", Greater Manchester Police said on Twitter. "There are now 17 searches either concluded or continuing at various addresses largely in the northwest of the country and we are getting a greater understanding of the preparation of the bomb", he said.
Four days after a suicide bombing plunged Britain into mourning, political campaigning resumed Friday for next month's general election with the main opposition leader linking deadly terrorism at home to foreign wars like the one in Libya.
May said that while she was at the summit rallying support for the fight against terrorism, "Jeremy Corbyn has said that terror attacks in Britain are our own fault, and he has said that just a few days after one of the worst terror attacks" in the country's history.
A poll on Thursday put May's Conservatives five points ahead of Labour suggesting a far tighter race than previously anticipated.