US Secretary of State Mike Pompeo has rejected a request by the House Foreign Affairs Committee to testify to five current and former officials in his department as part of the House probe to try President Donald Trump.
Pompeo accused Democrats of "trying to intimidate" diplomats who want to question them as part of the measure to isolate President Trump.
Democratic lawmakers were chairing three House committees that had scheduled a hearing on five top diplomats who could give them information about the conversation between Trump and Ukrainian President Volodymyr Zelinsky and his possible involvement in unconstitutional issues.
One of those diplomats was Kurt Volcker, the US special envoy to Ukraine, who resigned on Friday. .
Pompeo said in his letter that summoning these diplomats "can only be understood as an attempt to intimidate and offend senior professionals in the State Department."
In his letter, Pompeo referred to "profound procedural and legal flaws" in the summonses, and concluded that the deputies set a "very inappropriate time" in their request for diplomatic testimony.
With regard to his subpoena, Pompeo said he would respond by the weekend, the deadline, without any other indication of whether he would comply.