President Donald Trump on Tuesday said Prime Minister Theresa May was “foolish” in her handling of Brexit, as he doubled down on the feud with Britain’s ambassador to the U.S. Kim Darroch — whom he called “wacky,” “stupid” and a “pompous fool.”

“The wacky Ambassador that the U.K. foisted upon the United States is not someone we are thrilled with, a very stupid guy. He should speak to his country, and Prime Minister May, about their failed Brexit negotiation, and not be upset with my criticism of how badly it was handled,” he tweeted.

He then turned his ire toward May, who is leaving office

later this month after resigning over her handling of Britain’s departure from the E.U. Britain was scheduled to leave the bloc in March, but that timeline has been pushed back until October amid repeated failures to get her withdrawal agreement, negotiated with European leaders, through Parliament.

“I told @theresa_may how to do that deal, but she went her

own foolish way-was unable to get it done. A disaster!” Trump said, apparently referring to past advice that she sue the E.U. “I don’t know the Ambassador but have been told he is a pompous fool.”

The outburst came amid an escalating diplomatic spat over the leak of diplomatic cables in which Darroch called Trump’s administration “diplomatically clumsy and inept” and said he doubted it would become “substantially more normal.”

The memo was one of several cables published by the U.K.’s Mail on Sunday in which Darroch made negative statements about the U.S. government, in which he said that Trump could be at the mercy of “dodgy Russians,” and that Trump’s presidency could “crash and burn” and be at “the beginning of a downward spiral.”

He also reportedly indicated that Trump could win re-election, warning that he could shrug off scandals and “emerge from the flames, battered but intact, like [Arnold] Schwarzenegger in the final scenes of ‘The Terminator.”