U.S. Ambassador to the European Union Gordon Sondland arrives to testify before a House Intelligence Committee hearing as part of the impeachment inquiry into U.S. President Donald Trump on Capitol Hill in Washington, U.S., November 20, 2019.

President Donald Trump on Friday recalled U.S. Ambassador to the European Union Gordon Sondland, a key witness in House Democrats' impeachment inquiry, NBC News reported.

The move was reported hours after it was revealed that Army Lt. Col. Alexander Vindman, another witness in the impeachment proceedings, was recalled from his post as a National Security Council staffer.

David Pressman, a lawyer for Vindman, decried the action as an attempt by Trump to "exact revenge" against officials in his administration who cooperated with House Democrats.

Just two days earlier, the GOP-led Senate voted nearly along party lines to acquit Trump on two articles of impeachment that the House passed in December.

A day later, Trump lashed out at his perceived political enemies during a loud and lengthy victory lap.

"So many people have been hurt, and we can't let that go on," Trump said during remarks at the annual National Prayer Breakfast on Thursday morning.

The apparent purge of Sondland and Vindman — and Vindman's brother Yevgeny, who worked as an attorney at the National Security Council — came a day after Trump's remarks.