Suicide bomber Salman Abedi may have carried the powerful explosive used in the terror attack on Manchester Arena in a lightweight metal container concealed within either a black vest or a blue Karrimor backpack, according to reports published by The New York Times.
Abedi is also thought to have held the detonator in his left hand, the paper said, attributing the intelligence to "preliminary information gathered by British authorities".
The paper published crime scene photos of what appeared to be the blood-smeared silver detonator, with wires trailing from one end.
"The apparent detonator, which British law enforcement officials said was carried in the bomber's left hand, is also unusual for a manual detonator in a suicide device, in that it appears to have contained a small circuit board soldered inside one end," the paper reported.
"It is not clear from the law enforcement images if the object was a simple plunger switch, or included a timer or a receiver that could be operated remotely via radio signal – or some combination."
The Home Office declined to comment on the suggestion that the intelligence had been leaked by US authorities, just hours after Home Secretary Amber Rudd warned US officials not to share details about terror attacks, such as the Manchester bombing, before their UK counterparts.
Ms Rudd said she had reprimanded US officials who appear to have shared information with US media before it was released in the UK by British security services.
"I have been very clear with our friends that that should not happen again," she said, calling it "irritating" when information was released as British authorities continued their investigation.
There was no immediate response from Downing Street, but it is possible that Theresa May could raise the issue with President Donald Trump when they meet at the Nato summit in Brussels on Thursday.
Police and security agencies investigating the case regard it as crucial to the success of their operation to be able to control the release of information.
Abedi's name was circulating in the US media on Tuesday, hours before it was confirmed by UK police, who had earlier urged reporters not to publish speculation about the bomber's identity.
Additional reporting by agencies
