Lt. Col. Alexander Vindman, a key national security official who testified during the House impeachment inquiry, has been "escorted" from the White House, according to a statement from his lawyer.

Why it matters: Vindman testified before the House Intelligence Committee that President Trump's July 25 call with Ukrainian President Volodymyr Zelensky — which he listened in on — was "improper."

Trump told the White House press corps early Friday that he was "not happy with" Vindman.

What they're saying: "LTC Vindman was asked to leave for telling the truth," his attorney David Pressman said in the statement. "The truth has cost LTC Alexander Vindman his job, his career, and his privacy." Pressman said his client "was asked to leave for telling the truth," and that Trump "decided to exact revenge."

"He did what any member of our military is charged with doing every day: he followed orders, he obeyed his oath, and he served his country, even when doing so was fraught with danger and personal peril. And for that, the most powerful man in the world - buoyed by the silent, the pliable, and the complicit - has decided to exact revenge."

— Alexander Vindman's lawyer, David Pressman

Vindman's twin brother, “Lieutenant Colonel Yevgeny Vindman, a senior lawyer and ethics official at the National Security Council, and a decorated Iraq war veteran, was escorted off of the grounds of the White House, suddenly and with no explanation, despite over two decades of loyal service to this country," Pressman added. "He is deeply disappointed that he will not be able to continue his service at the White House.”

"We do not comment on personnel matters," NSC spokesperson John Ullyot told Axios.

Go Deeper: Trump retweets congressman calling for Alexander Vindman's firing