A handful of US representatives have reacted furiously to a leaked recording in which the special envoy to Ukraine reportedly coached Moscow on how to handle Donald Trump, but most have so far remained mute on the revelation that American officials were advising a US adversary.

Don Bacon, a Republican representative, called for Steve Witkoff’s immediate dismissal. “For those who oppose the Russian invasion and want to see Ukraine prevail as a sovereign & democratic country, it is clear that Witkoff fully favors the Russians,” the Nebraska lawmaker wrote on X.

“He cannot be trusted to lead these negotiations. Would a Russian paid agent do less than he? He should be fired.”

Brian Fitzpatrick, a Pennsylvania Republican wrote that the leak represented “a major problem” and “one of the many reasons why these ridiculous side shows and secret meetings need to stop”. He urged that the secretary of state, Marco Rubio, be allowed to “do his job in a fair and objective manner”.

Democratic representative Ted Lieu went further, calling Witkoff an “actual traitor,” and adding: “Steve Witkoff is supposed to work for the United States, not Russia.”