Britain raced to hunt down a militant's network thought to be behind the Manchester concert attack, as a row escalated between London and Washington over leaked material from the probe.
As more children were named among the 22 victims of Monday's massacre, Libyan authorities detained the suicide bomber's father as well as his brother and police in Britain also carried out new arrests and raids.
In Manchester, northwest England, feelings were still raw following Salman Abedi's attack on a concert by U.S. pop star Ariana Grande -- especially so as the bomber was born in the city.
But amid the grief, British authorities were left "furious" by repeated leaks of material shared with their U.S. counterparts, providing an awkward backdrop for Prime Minister Theresa May's meeting with US President Donald Trump at the NATO summit in Brussels later Thursday.
Images obtained by The New York Times newspaper showed a detonator Abedi was said to have carried in his left hand, shrapnel including nuts and screws and the shredded remains of a blue backpack. "We are furious. This is completely unacceptable," a government ministry source said of the images "leaked from inside the U.S. system".
The leak, which followed a similar leak of the bomber's identity and probe details, has rocked the intelligence-sharing relationship between close allies London and Washington.
The National Counter Terrorism Policing body said the breach of trust caused great "damage" and "undermines our investigations."
University dropout Abedi, 22, grew up in a Libyan family that reportedly fled to Manchester to escape the now-fallen regime of Libyan strongman Muammar Qaddafi. He transited through Istanbul airport ahead of carrying out the attack, a Turkish official said. "I can confirm that he transited through Istanbul Ataturk" airport, the official told AFP, asking not to be named and referring to the country's main international airport. The official said no intelligence had been shared with Turkey concerning the bomber, Salman Abedi, ahead of his presence in Istanbul. German police have said he had made a brief stopover at Duesseldorf Airport to change planes.
A spokesman for the Deterrence Force, which acts as Libya's Government of National Accord's police, said the brother was aware of Abedi's plan and the siblings were both members of Daesh. The attack was the latest in a series of deadly incidents across Europe claimed by Daesh that have coincided with an offensive on the group in Syria and Iraq carried out by U.S., British and other Western forces.
Hashem had been "under surveillance for a month and a half" and "investigation teams supplied intelligence that he was planning a terrorist attack in the capital Tripoli", the Deterrence Force said on its Facebook page. A relative told AFP that Abedi had travelled to Manchester from Libya four days before the bombing.
British officials said Abedi had been on the radar of the intelligence community before the massacre. "It's very clear that this is a network that we are investigating," Manchester police chief Ian Hopkins told reporters. Police announced two new arrests yesterday in their probe, bringing the total to eight people in custody in Britain. A woman detained on Wednesday was released without charges.
Britain's terror threat assessment has been hiked to "critical", the highest level, meaning an attack is considered imminent. Armed troops were sent to guard key sites, a rare sight in mainland Britain.
The attack was the deadliest in Britain since 2005 when four Islamist suicide bombers attacked London's transport system, killing 52 people. The bombing came just over two weeks before a snap general election set for June 8.