WASHINGTON (AP) — President Donald Trump is lashing out at a pair of witnesses who are set to testify as the House impeachment inquiry goes public.

Trump tweeted “NEVER TRUMPERS!” before Wednesday’s hearing opened on Capitol Hill with testimony from William Taylor, the charge d’affaires in Ukraine, and George Kent, a career diplomat. Trump sought to undermine Kent and Taylor with the tweet suggesting they are among members of the foreign policy establishment that never supported him.

Taylor and Kent worked for Republican and Democratic administrations. There’s no evidence they engaged in partisan activity opposing Trump.

The impeachment inquiry centers around a July 25 telephone call Trump had with Ukraine’s leader and Trump’s attempt to pressure the government to investigate his political rivals.

Trump maintains that the telephone conversation was “perfect” and that he did nothing wrong in his relations with Ukraine.

The Republican president also tweeted Wednesday: “READ THE TRANSCRIPT!”