British Prime Minister Theresa May raised concerns with U.S. President Donald Trump on Thursday over leaks to U.S. media about the Manchester suicide bombing, a British government source said.
May raised the issue of the intelligence leaks with Trump while they were waiting for a group photograph to be taken at a NATO summit in Brussels. Television pictures showed May and Trump talking while sitting side-by-side at the event.
"She expressed the view that the intelligence sharing relationship we have with the U.S. is hugely important and valuable, but that the information that we share should be kept secure," the source said.
The source also said that Britain was prepared to increase non-combat troop deployment to the NATO mission in Afghanistan.
On the matter, Trump said the leaks were "deeply troubling," promising an investigation after British police said the publication of forensic photographs had caused distress to victims' relatives.
"These leaks have been going on for a long time and my administration will get to the bottom of this," Trump said in a statement released by the White House as he arrived at NATO headquarters in Brussels.
"The leaks of sensitive information pose a grave threat to our national security."
Trump said he was ordering a review by the Justice Department and other agencies and "if appropriate, the culprit should be prosecuted to the fullest extent of the law."
In London, Lew Lukens, the acting U.S. ambassador, also promised that "appropriate steps will be taken" following an investigation of the leaks.
Lukens said Washington will "continue to offer resources and intelligence to assist the UK authorities in their investigation."
Greater Manchester Police Chief Constable Ian Hopkins told reporters that the leaked forensic photographs from Manchester Arena, published by the New York Times overnight, had "caused much distress for families that are already suffering terribly with their loss."
But he declined to comment on reports that his force had stopped sharing intelligence on the Manchester attack with the United States.
The New York Times defended publishing the leaked photographs from the scene of the attack, which killed 22 people and injured dozens at the end of a concert by U.S. popstar Ariana Grande.
The U.S. newspaper's coverage of the bombing was "both comprehensive and responsible" and the paper has strict guidelines on how to cover sensitive stories, a spokeswoman for the newspaper said in a statement.
"The images and information presented were neither graphic nor disrespectful of victims, and are consistent with the common line of reporting on weapons used in horrific crimes, as The Times and other media outlets have done following terrorist acts around the world, from Boston to Paris to Baghdad, and many places in between," the statement read.
The BBC said British officials were "outraged" by the publication of the images.
The leak came after the name of the alleged attacker, 22-year-old Salman Abedi, was reported by US media on Tuesday, quoting US officials, before British police had released it publicly.