BREAKING NEWS: Hashem Abedi, younger brother of Manchester attacker, arrested in Tripoli on suspicion of Islamic State links. He was planning 'terrorist act'- counter-terrorism police said. Police say have arrested sixth person in connection with Manchester bomb attack after raid
Hashem Abedi, 20, younger brother of Salman Abedi, Manchester Arena suicide bomber
Many people including some children killed in a suicide attack carried out by one man after a Ariana Grande concert in Manchester.
The Manchester attacker, Salem Abedi, was part of a network, the city's chief of police said on Wednesday as troops deployed across Britain to help prevent further attacks.
A source said investigators were hunting for accomplices who may have helped build the suicide bomb and who could be ready to kill again.
"I think it's very clear that this is a network that we are investigating," police chief Ian Hopkins said outside Manchester police headquarters.
"And as I've said, it continues at a pace. There's extensive investigations going on and activity taking place across Greater Manchester as we speak."
Earlier, interior minister Amber Rudd said the bomber, Salman Abedi, had recently returned from Libya. Her French counterpart Gerard Collomb said he had links with Islamic State and had probably visited Syria as well.
Rudd scolded U.S. officials for leaking details about the investigation into the Manchester attack before British authorities were prepared to go public.
The Manchester bombing has raised concern across Europe. Cities including Paris, Nice, Brussels, St Petersburg, Berlin and London have suffered militant attacks in the last two years.
British-born Abedi, 22, blew himself up on Monday night at the Manchester Arena indoor venue at the end of a concert by U.S. pop singer Ariana Grande attended by thousands of children and teenagers.
His 22 victims 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.
Britain's official terror threat level was raised to "critical", the highest level, late on Tuesday, meaning an attack was expected imminently.
The vigil, held in warm evening sunshine in front of the Town Hall, drew representatives of different religions who, one by one, condemned Monday evening's bombing, which ripped through a crowd leaving a show by U.S. singer Ariana Grande.
Members of the city's Muslim, Christian, Jewish and Sikh communities said they wanted to show that Manchester, while shocked, would not be cowed.
"It was incredibly emotional ... for us especially as Muslim citizens," said Muhammad Khursheed, an imam of a mosque in the Manchester suburb of Hulme. "We will stand together in spite of oppression, terrorism. A strong, powerful message today."
Salman Abedi, 22, Manchester Arena suicide bomber
British police on Tuesday identified the suicide bomber as 22-year-old Salman Abedi but gave no further details. U.S. security officials, citing British intelligence officials, said Abedi was born in Manchester to Libyan parents.
After speeches by officials, people attending the vigil gathered in small groups to talk among themselves. Some students took turns to hug a woman dressed in a burka.
"Together. Unified," Daniel Liptrott, a 45 year-old businessman said when asked how the vigil made him feel. "A single act of terrorism isn't going to break that."
After a moment of silence, when many wept, the crowd broke into repeated chants of "Manchester, Manchester."
A placard read: "Hate will never tear us apart", alluding to the song "Love will tear us apart" by Joy Division, one of Manchester's best known music groups.
Fans of the city's rival soccer teams Manchester United and Manchester City stood together at the protest.
A local poet, Tony Walsh, read a poem from the steps of the Town Hall to the crowd which drew loud cheers and applause.
"There's hard times again in these streets of our city, but we won't take defeat and we don't want your pity, because this is the place where we stand strong together with a smile on our face, Mancunians forever," Walsh said.
(Writing by William Schomberg; Editing by Gareth Jones)