UK police launched a “criminal investigation” into the leak of British diplomatic cables that criticised US President Donald Trump and his administration, calling it “inept” on Saturday.

London’s Metropolitan Police said that its terrorism command which investigates potential breaches of Britain’s Official Secrets Act had initiated the probe into the leaking of Kim Darroch’s correspondence.

“I am satisfied that there has been damage caused to UK international relations, and there would be a clear public interest in bringing the person or people responsible to justice,” Assistant Commissioner Neil Basu said in a statement while announcing the move.

On Friday, the American president said that Britain needed to stop their “leaking problems”.

The British government had opened its own inquiry into the leaks this week and noted it had involved the police to ascertain whether any documents protected by the Official Secrets Act had been shared.

Basu said that the leaks may be a “criminal matter” as he urged the culprit to “turn yourself in at the earliest opportunity, explain yourself and face the consequences”.

“Also, to anyone who knows or suspects those responsible, or who has any information, please come forward,” he added.

After Trump said he would no longer work with Darroch, and he was disinvited from several events, Kim Darroch had stepped down as the UK Ambassador to the US on Wednesday.

Darroch wrote a letter while announcing his resignation, saying, “Since the leak of official documents from this Embassy there has been a great deal of speculation surrounding my position and the duration of my remaining term as ambassador. I want to put an end to that speculation”.

The emails were leaked to the Mail newspaper on Sunday.

Meanwhile, British Prime Ministerial contender Boris Johnson had earlier refused to rule out the firing of Darroch.

However, US President Donald Trump slammed UK envoy and said, “The ambassador has not served the UK well, I can tell you that”.

In a series of tweets, Trump wrote, “The wacky Ambassador that the UK foisted upon the United States is not someone we are thrilled with, a very stupid guy”.