The father and the younger brother of the suicide bomber who killed 22 people at a concert venue in Manchester have been arrested in Tripoli, a spokesman for a local counter-terrorism force said on Wednesday.
The counter-terrorism force detained the father, Ramadan Abedi, outside his home in the Tripoli suburb of Ayn Zara on Wednesday afternoon. A witness said he was handcuffed by armed men who drove him away in two unmarked vehicles.
The force, known as Rada, detained the brother Hashem Abedi, who was born in 1997, on Tuesday evening on suspicion of links to Islamic State, spokesman Ahmed Bin Salem said. He did not give any details on the reasons why the father was arrested.
But Hashem Abedi had been in touch with attacker Salman Abedi, Bin Salem said, and was suspected of planning to carry out an attack in the Libyan capital.
"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."
He said the younger brother had traveled from London to Tripoli on April 16.
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. His father lives in Tripoli.
Meanwhile, British police made three arrests and searched an address in central Manchester in what police chief Ian Hopkins described as a fast-moving investigation into the "network" surrounding Salman Abedi, the 22-year-old suicide bomber who killed 22 people at a concert venue packed with children on Monday night.
"I think it's very clear that this is a network that we are investigating," Hopkins told reporters 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 could be imminent.
Rudd said up to 3,800 soldiers could be deployed on Britain's streets, taking on guard duties to free up police to focus on patrols and investigation. An initial deployment of 984 had been ordered, first in London and then elsewhere.
Soldiers were seen at the Houses of Parliament, Prime Minister Theresa May's Downing Street residence and at London police headquarters at New Scotland Yard.
A source close to the investigation into the bombing told Reuters that the focus was on whether Abedi had received help in putting together the bomb and on where it had been done.
The BBC reported that security services thought the bomb was too sophisticated for Abedi to have built by himself.
Police arrested three people in South Manchester on Wednesday, bringing the total number of arrests related to the attack to four. A man arrested on Tuesday was reported by British and U.S. media to be Abedi's brother.
Police also said that they had searched an address in central Manchester as part of the investigation and had briefly closed a railway line in order to do so safely but that it had now been re-opened.
In London, the Changing of the Guard ceremony at Buckingham Palace, a draw for tourists, was cancelled because it requires support from police officers, which authorities decided was not a good use of police resources given the threat level.
Chelsea soccer club said it had cancelled a victory parade that had been scheduled to take place on Sunday to celebrate its Premier League title.
Several high-profile sporting events are coming up in Britain, including the soccer FA Cup final at London's Wembley Stadium and the English rugby club competition final at Twickenham on Saturday and the UEFA Champions League final at Cardiff's Millennium Stadium on June 3.