President Donald Trump lashed out at U.K. Prime Minister Theresa May and U.K. Ambassador to the U.S. Kim Darroch on Monday in the wake of leaked internal memos in which Darroch called the Trump administration “inept” and “uniquely dysfunctional.”

British newspaper The Mail on Sunday published snippets of the memos from Darroch to the British Government that date from 2017 to the present, and include many comments critical of the Trump administration.

“We will no longer deal with him,” Trump said in a tweet on Monday referring to Darroch. “I do not know the Ambassador, but he is not well liked or thought of within the US.”

Trump added that May and her administration have created “a mess” by not following his advice on Brexit.

“We have made clear to the U.S. how unfortunate this leak is. The selective extracts leaked do not reflect the closeness of, and the esteem in which we hold, the relationship,” a spokesperson for Downing Street told CNBC. “At the same time we have also underlined the importance of Ambassadors being able to provide honest, unvarnished assessments of the politics in their country. Sir Kim Darroch continues to have the Prime Minister’s full support.”

The White House, U.K. Embassy in the U.S., and U.K. Foreign Secretary did not immediately respond to requests for comment. The State Department referred a request for comment to the White House.

Trump’s tweets follow comments to reporters on Sunday in which Trump also lambasted Darroch.

“The ambassador has not served the U.K. well, I can tell you that,” he said. “We’re not big fans of that man.”

The U.K.’s international trade minister Liam Fox defended Darroch on Monday and criticized the leaker, saying the breach could damage the U.S. and U.K’s “special relationship.”

Trump’s comments follow past swipes at Prime Minister May over Brexit.

In interviews with British tabloid The Sun in 2018 and 2019, which occurred close to his visits to the U.K., Trump said May had bungled negotiations with the EU.

“I think that the UK allowed the European Union to have all the cards. And it is very hard to play well when one side has all the advantage,” Trump told The Sun in May. “I had mentioned to Theresa that you have got to build up your ammunition.”

The president has also taken shots at Darroch in the past. Prior to taking office, Trump called for U.K. politician Nigel Farage, a leading voice for Brexit and an opponent of May, to become the U.K.’s ambassador to the U.S., replacing Darroch.

At the time, the U.K. government defended Darroch. Then-Foreign Secretary Boris Johnson said Darroch was “first rate” and there is “no vacancy for that position.”

Johnson is now widely expected to become the U.K.’s next prime minister. Trump praised him in his 2018 interview with The Sun, and floated him as a potential replacement for May.

“I have a lot of respect for Boris. He obviously likes me, and says very good things about me,” Trump said.

“The U.K. has a special and enduring relationship with the U.S. based on our long history and commitment to shared values and that will continue to be the case,” a spokesperson for Downing Street told CNBC.