Lt. Col. Alexander Vindman, National Security Council Director for European Affairs, arrives to testify before the House Intelligence Committee in the Longworth House Office Building on Capitol Hill November 19, 2019 in Washington, DC.

WASHINGTON — President Donald Trump said Tuesday that the Pentagon could look at disciplinary action against U.S. Army Lt. Col. Alexander Vindman, a key figure who testified in the Ukraine impeachment saga.

On Friday, Vindman, a former National Security Council staffer, was escorted out of his third-floor office across from the White House. The Senate had acquitted Trump of two impeachment articles, abuse of power and obstruction of Congress, on Wednesday.

"We're going to have to see, but if you look at what happened, they're going to certainly, I would imagine, they're going to take a look at that," Trump said in the Oval Office on Tuesday, when he was asked whether the Defense Department would seek disciplinary action against Vindman.

"He is over with the military," Trump added from the Oval Office. "We sent him on his way to a much different location and the military can handle him any way they want," Trump said, referring to Vindman's reassignment from the White House to the Department of the Army.

National security advisor Robert O'Brien said Tuesday that there was "no retaliation" and Trump didn't instruct him to remove Vindman and his twin brother, Yevgeny Vindman, from their White House posts, according to reports.

The Pentagon declined to comment on the president's comments Tuesday.

Hours before Vindman was escorted from his office Friday, Trump had said of the Purple Heart recipient: "I'm not happy with him."

"Do you think I'm supposed to be happy with him?" Trump asked reporters Friday. "I'm not."

Earlier Friday, Defense Secretary Mark Esper was asked whether Vindman would be welcomed back to the department if he left the National Security Council, and what the Pentagon would do to ensure that he is "not retributed against by the president or others?"

"We welcome back all of our service members, wherever they serve, to the assignment they're given," Esper said. "We protect all of our persons, service members from retribution or anything, anything like that."

Esper's comments on Vindman came after he issued a memo to all Department of Defense employees and military personnel to "uphold DoD's longstanding tradition of remaining apolitical."