Vindman told a Democratic-run committee “I couldn’t believe what I was hearing” in the phone call. Trump asked Zelensky to launch investigations into both Democratic rival Joe Biden and a widely debunked conspiracy theory that Ukraine, not Russia, was behind meddling in the 2016 US presidential election.
In that appearance, Vindman also downplayed concerns that he would suffer payback for speaking out. “I will be fine for telling the truth,” he said.
A spokesman for the NSC declined to comment.
Trump emerged victorious from his trial this week with a vote in the Senate, controlled by fellow Republicans who rejected abuse of power and obstruction of justice charges.
Asked earlier on Friday about media reports that he might remove Vindman, Trump told reporters: “I’m not happy with him. You think I’m supposed to be happy with him?…They’re going to be making that decision.”
A source familiar with the situation told Reuters that Vindman would be reassigned to the Defense Department.
Vindman’s two-year stint at the White House was due to end in July.
US Defence Secretary Mark Esper said on Friday that the Pentagon protects all service members from retribution.
Trump, who became only the third US president to be impeached, has said he is still bitter as he turns his attention to seeking a second four-year term in the November 3 presidential election.
Another senior white House aide who testified over impeachment, Jennifer Williams, left this week for a post at the US military’s Central Command, according to Bloomberg News.
Trump has cast both Vindman and Williams as “Never Trumpers” who oppose him.
Trump denied reports that he was weighing a permanent chief of staff to replace acting aide Mick Mulvaney, who was a central figure in the impeachment inquiry.
“That was a false report. I have a great relationship with Mick,” Trump said.
Democrats say Trump pushed for the Ukraine investigations to undermine Biden, a candidate to win the Democratic nomination for November’s election. Trump says he wanted to help Ukraine fight corruption.
Biden’s presidential campaign suffered a serious setback when he came in fourth place at the Democrats’ first state nominating contest in Iowa this week.
Senate Republicans have been investigating Hunter Biden, who served on the board of a Ukrainian gas company while his father, Joe, was US vice president.
Senators Chuck Grassley and Ron Johnson have asked for the younger Biden’s travel records while under official Secret Service protection, among other official records. Democratic lawmakers say the Treasury Department has provided Congress with some financial records involving Hunter Biden.
Trump had urged Ukraine to investigate both Bidens, though there has been no evidence of wrongdoing by either one.