UPDATED 3:55pm Manchester police have released the woman they took into custody following a terror attack on Tuesday.
She was one of seven people arrested in the UK with a connection to the suicide bombing on Manchester Arena which claimed 22 lives.
Manchester Police say it's clear the bomber had a network of accomplices.
The father and the younger brother of the suicide bomber responsible for the attack have been arrested in Tripoli on suspicion of links with Islamic State, a spokesman for a local counter-terrorism force says.
LISTEN ABOVE: UK Correspondent Enda Brady speaks with Larry Williams about the latest on the attack
The force, known as Rada, detained Hashem Abedi, who was born in 1997, on Tuesday evening, spokesman Ahmed Bin Salem told Reuters.
Hashem Abedi had been in touch with attacker Salman Abedi, Bin Salem said, and had travelled from Libya to Britain last month.
"We have evidence that he is involved in Daesh (Islamic State) with his brother. We have been following him for more than one month and a half," Bin Salem said.
"He was in contact with his brother and he knew about the attack."
Salman Abedi, 22, was born in Britain to Libyan parents. Britain's interior minister said earlier that he had recently returned from Libya and had likely not acted alone.
Reuters have reported that his father, Ramadan, was also arrested on Wednesday, quoting a spokesman and a witness.
Those arrests are on top of several in the United Kingdom with a man in Wigan is the latest to be arrested in the wake of the attack.
Police are examining a package he had with him as he was arrested.
The head of Greater Manchester Police Chief Constable Ian Hopkins told reporters:Â "I think it's very clear that this is a network that we are investigating," Â told reporters.
"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."
Hopkins declined to elaborate, but he confirmed that an off-duty policewoman died in the attack, which came at the end of a concert by US singer Ariana Grande.
The official threat level in Britain was raised late on Tuesday for the first time in a decade to its highest level, "critical", meaning an attack could be imminent.
It came as three men were arrested in Manchester on Wednesday as part of the investigation into the suicide bomb attack.
Interior minister Amber Rudd said up to 3800 soldiers would be deployed on Britain's streets, taking on guard duties at places like Buckingham Palace and Downing Street to free up police to focus on patrols and investigatory work.
Ariana Grande has suspended her Dangerous Woman tour following the attack.
A spokesman for the 23-year-old announced the decision on Wednesday evening following widespread speculation that dates would be affected.
Grande's next engagements were two nights at the O2 Arena in London on Thursday and Friday before heading to mainland Europe.
There has been no word on the six-date tour of Australia and New Zealand scheduled for September.
"We are deeply saddened by this senseless tragedy and our hearts and thoughts are with those impacted by this devastating incident," promoters Live Nation said in a statement.
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