Gov. Kevin Stitt of Oklahoma told Democratic governors on Wednesday that President Trump had reversed course and would now invite them to an annual gathering of the nation’s governors at the White House, after the president had previously moved to exclude Democrats from the meeting.

Hours later, Mr. Trump repeatedly attacked Mr. Stitt, the chairman of the National Governors Association, as a “RINO,” Republican in name only, apparently blaming the governor for the episode after The New York Times reported last week that the president had spurned Democrats from what had traditionally been a bipartisan working meeting with the president and cabinet at the White House.

Mr. Stitt confirmed the reporting in a letter to governors on Friday and withdrew the N.G.A. as the official organizer of the event, saying that it would not pay for transportation to the gathering and that the association sought to represent all governors.

In a social media post, Mr. Trump denied that he had ever tried to exclude Democrats from the meeting — though by Tuesday night, only Republican governors had received invitations for the meeting scheduled for Friday. He did, however, confirm that he had personally blocked two Democrats, Gov. Wes Moore of Maryland and Gov. Jared Polis of Colorado, from a separate black-tie dinner that would take place after the meeting because he felt they were “not worthy of being there.”

In his statement, Mr. Trump said he had blocked Mr. Polis as part of his pressure campaign to release Tina Peters, a former Colorado county clerk who was convicted of tampering with voting machines after the 2020 election in a failed effort to prove Mr. Trump’s false claims that the election was stolen from him. Mr. Trump symbolically pardoned Ms. Peters last year, but the president has no legal power to pardon state crimes, leaving Mr. Polis as the only person with the power to pardon her.

“I look forward to seeing the Republican Governors,” Mr. Trump said in his post. “And some of the Democrats Governors who were worthy of being invited, but most of whom won’t show up.”