The White House is blaming Lt. Col. Alexander Vindman for misleading reporters about the contents of an April 21 phone call between President Trump and Ukrainian President Volodymyr Zelensky.

Vindman is the top Ukraine official on the White House National Security Council. On Friday, the White House released a rough transcript of the call that conflicts with a separate summary of the call sent to reporters in April.

The April summary of the call said that Trump "underscored the unwavering support of the United States for Ukraine’s sovereignty and territorial integrity – within its internationally recognized borders – and expressed his commitment to work together with President-elect Zelensky and the Ukrainian people to implement reforms that strengthen democracy, increase prosperity, and root out corruption."

The rough transcript of the phone call documents Trump congratulating Zelensky on his election victory and pledging to send a "very, very high level representative" to attend Zelensky's inauguration. However, it does not include Trump explicitly promising to work with Zelensky to "strengthen democracy, increase prosperity, and root out corruption" in Ukraine.

In response to questions from reporters, the White House said in a Friday statement that "the NSC's Ukraine expert" prepared the April summary.

"The president continues to push for transparency in light of these baseless accusations and has taken the unprecedented steps to release the transcripts of both phone calls with President Zelensky so that every American can see he did nothing wrong. It is standard operating procedure for the National Security Council to provide readouts of the president's phone calls with foreign leaders," deputy White House press secretary Hogan Gidley said.

"This one was prepared by the NSC's Ukraine expert," he added, an apparent reference to Vindman.

The April 21 phone call happened three months before a July 25 phone call between the two world leaders that is now at the center of House Democrats' impeachment effort against Trump. Lawmakers are investigating allegations that Trump withheld military aid from Ukraine to secure an investigation into former Vice President Joe Biden, which could give him political advantage over the 2020 Democratic front-runner.

Vindman, who has already provided a closed-door deposition in the impeachment process, is set to testify in a public hearing on Tuesday.