BRUSSELS (CNN) - Intelligence sharing between the US and the UK resumed Thursday shortly after British Prime Minister Theresa May met with her US counterpart President Donald Trump.
It came after a series of high-profile leaks to US media of details surrounding the Manchester bombing investigation, which were blamed on US government officials.
The breakdown of trust between the two countries briefly led to the suspension on the sharing of intelligence Thursday. An incensed May confronted Trump about the leaks during their meeting at the NATO headquarters in Brussels.
In a written statement, President Trump described the leaks as "deeply troubling."
"These leaks have been going on for a long time and my administration will get to the bottom of this. The leaks of sensitive information pose a grave threat to our national security. I am asking the Department of Justice and other relevant agencies to launch a complete review of this matter, and if appropriate, the culprit should be prosecuted to the fullest extent of the law."
"There is no relationship we cherish more than the special relationship between the United States and the United Kingdom," the President said in the statement.
As she arrived at the NATO summit, May made it clear she would be bringing up the issue of leaks in her meeting with Trump, which came three days after a suicide bomber killed 22 people and injured dozens at an Ariana Grande concert in the UK city of Manchester.
She said when it came to intelligence sharing, the US and the UK had a "special relationship," adding "it's our deepest defense and security partnership."
"Of course that partnership is built on trust and part of that trust is knowing that intelligence can be shared confidently, and I will be making clear to President Trump today that intelligence that is shared between law enforcement agencies must remain secure."
Trump ignored shouted questions about whether Britain could trust the US with its intelligence as he was greeting French President Emmanuel Macron outside the US Chief of Mission's residence ahead of talks.
Inside, Trump ignored the questions again, mouthing "thank you" before dismissing reporters from the room.
British officials were fuming that information about the attack had surfaced in the US press after it was shared with their American counterparts.
It has put a shadow over the fourth stop on Trump's first foreign trip, which has also brought him to Saudi Arabia, Jerusalem and Rome.
Back home, new questions were also surfacing about alleged ties between Trump's campaign and Russia, a storyline Trump had hoped to escape during his international foray.
Manchester Mayor Andy Burnham said earlier the decision to stop sharing information was taken because they couldn't "afford to risk it anymore."
"(The investigation) has been compromised by the leaks and we can't afford anymore, so we've taken a temporary decision to say, 'let's clear it out and draw a line, let's not have a row that lingers on.' Nobody wants that, but equally we have to make our opinions clear so we can get this relationship back to where we all want it to be," Burnham told CNN.
The intelligence dust-up had threatened to dampen Trump's formal introduction to leaders at NATO, the first heads-of-state gathering that Trump has attended since taking office.
Trump has met most of the leaders during visits to the White House, but his appearance in Brussels offered the first opportunity for him to hold broader discussions with his counterparts.
The United States and Britain are both participants in the "Five Eyes" intelligence sharing pact between English-speaking nations. The leader of another member, Canadian Prime Minister Justin Trudeau, declined to answer directly Thursday whether he was reconsidering his country's intelligence agreement with the United States.
"The track record has shown collaboration and cooperation between allies," Trudeau said ahead of the NATO talks. "We will continue to collaborate and work together to ensure we do everything we can to keep citizens and communities safe."
Fighting extremism has been a central theme of Trump's first trip abroad. The Manchester terror attack has added urgency to the President's argument.
"When you see something like what happened a few days ago, you realize how important it is to win this fight," Trump said Wednesday night at the Royal Palace. "We will win this fight. It's a horrible situation, what took place is horrible. Unthinkable. But we will win."
Trump's administration has faced questions at multiple points this month about the sanctity of intelligence shared by foreign governments.
In a meeting with Russian officials on May 10, Trump revealed highly classified details about a plane bombing plot. The information was gleaned from the Israeli intelligence services, and was said to be so detailed that its origin would be obvious.
Visiting Israel earlier this week, Trump insisted during an off-script moment that he never mentioned Israel by name with his Russian guests. But neither he nor the White House have disputed that he discussed the airliner plot with the Russian foreign minister and ambassador in Washington.
After Trump departed Jerusalem on Tuesday, Israeli Defense Minister Avigdor Liberman said the two governments had discussed the matter and made a "pointed correction."
"Everything we needed to discuss was discussed," Liberman said. "We did an inquiry. Everything that should have been done -- all the conclusions -- everything was done."
Israel's Prime Minister Benjamin Netanyahu said alongside Trump that intelligence coordination between his government and the United States was "terrific."
Earlier this week, it was revealed that Trump told Philippines President Rodrigo Duterte the US had dispatched two nuclear submarines to waters off the Korean peninsula, raising further questions about the President's handling of sensitive information.
The revelation came from a leaked transcript of an April 29 phone call between the two leaders.