The suicide bombing at a packed concert in Manchester was the deadliest attack in Britain since July 2005, when four British Muslim suicide bombers killed 52 people in coordinated attacks on London's transport network.
British Prime Minister Theresa May chaired a meeting Wednesday of her emergency security cabinet group to talk about intelligence reports on Abedi and concerns that he might have had outside support.
Hopkins, the Manchester police chief, said the leaks had "caused much distress for families that are already suffering terribly with their loss". "These leaks have been going on for a long time, and my administration will get to the bottom of this".
8pm: Rudd says Manchester suicide bomber Salman Abedi was known "up to a point" to the British intelligence services and police.
In addition to those killed in the concert attack, 64 people are being treated for their wounds, Jon Rouse of the Greater Manchester Health and Social Care Partnership said Wednesday.
"She expressed the view that the intelligence sharing relationship we have with the USA is hugely important and valuable, but that the information that we share should be kept secure", a British Government source said.
Ballons and flowers are seen in Albert Square in central Manchester.
Rudd's comments come in the wake of revelations that U.S. President Donald Trump shared highly classified information, reportedly obtained from Israeli intelligence services, with Russian officials earlier this month. The disclosure of potential evidence "undermines our investigations and the confidence of victims, witnesses and their families".
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Metropolitan Police Assistant Commissioner Mark Rowley said: "We are moving at pace, we are making arrests, we are doing searches but - not unsurprisingly - there are still gaps in our knowledge".
Rudd told the BBC she believed Abedi had recently returned from Libya, and French Interior Minister Gerard Collomb said British investigators had told French authorities Abedi had probably travelled to Syria as well.
But it was not clear USA officials were the source of the images, which the Times defended as "neither graphic nor disrespectful of victims" and consistent with basic reporting "on weapons used in horrific crimes".
A senior unnamed Whitehall source told The Guardian that protests had been lodged at every relevant level with the US.
At the Abedi family home in Elsmore Road, a nondescript red-brick terrace, neighbours said Abedi had become increasingly devout and withdrawn. Upon her arrival in Brussels, May said the U.S.
A German security official told the AP on Thursday the report was accurate, speaking on condition of anonymity because the information hadn't been cleared for public release.
Israel and the United Kingdom are America's closest allies in intelligence-sharing.
A British army soldier and a police officer secure an entrance to the defence ministry in London.
But as more information emerged about the attacker another possibility was raised: that he was trained in bomb-making at a terrorist camp in Libya. "We did our checks", he added, declining to discuss details.