An aide who testified against President Donald Trump in the impeachment hearings has been escorted out of the White House, says his lawyer.
Lt Colonel Alexander Vindman has been transferred from the National Security Council (NSC) back to the Pentagon.
The White House Ukraine expert’s attorney said his client “was asked to leave for telling the truth”.
Mr Trump is said to desire a staff shake-up after senators cleared him in the impeachment case on Wednesday.
How was Vindman removed?
Lt Col Vindman’s counsel, David Pressman, told the BBC his client had been “escorted out of the White House where he has dutifully served his country and his President”.
“There is no question in the mind of any American why this man’s job is over, why this country now has one less soldier serving it at the White House,” said the statement.
“LTC Vindman was asked to leave for telling the truth. His honour, his commitment to right, frightened the powerful.”
It added: “The truth has cost LTC Alexander Vindman his job, his career, and his privacy.”
The statement continued: “The most powerful man in the world – buoyed by the silent, the pliable, and the complicit – has decided to exact revenge.”
Lt Col Vindman had reportedly turned up for work at the White House as usual on Friday.
What did Trump and his administration say?
As he left the executive mansion on Friday for North Carolina, Mr Trump told reporters: “I’m not happy with him [Lt Col Vindman].
“You think I’m supposed to be happy with him? I’m not.”
A Pentagon official said Lt Col Vindman will go to the Department of the Army for assignment until his Army War College class starts this summer.
According to White House sources, Lt Col Vindman had been expecting a transfer. He was telling colleagues for weeks that he was ready to move back to the defence department, where he still holds active-duty soldier status.
Earlier on Friday, US Defence Secretary Mark Esper told reporters his department welcomes back all of its personnel from assignment.
“And as I said we protect all of our service members from retribution or anything like that,” Mr Esper added.
How did Vindman annoy Trump?
Lt Col Vindman testified to a House impeachment panel last November. He said he was “concerned” after hearing Mr Trump’s “improper” phone call on 25 July last year with Ukraine’s president.
The call led to Mr Trump’s impeachment in December by the House for abuse of power and obstruction of Congress.
Democratic lawmakers argued that the president had dangled US aid in exchange for political favours.
When asked how he had overcome his fear of retaliation in order to testify, Lt Col Vindman testified: “Congressman, because this is America… and here, right matters.”
What’s the reaction?
Top Democratic Senator Chuck Schumer said the Pentagon had assured him in December that “patriots and whistleblowers” like Lt Col Vindman would be protected.
“Any reprisals against him or others who came forward to tell the truth are wrong and should be seen for what they are: An extension of President Trump’s cover-up.”
But Republican Congressman Thomas Massie said he would have fired Lt Col Vindman.
“He’s a leaker, not a whistleblower,” Mr Massie said. “Current Commander in Chief doesn’t take orders from a Lt Col!”
Is Mick Mulvaney next?
In his comments to media on Friday, Mr Trump said reports that Mr Mulvaney would be fired were “false”.
“I have a great relationship with Mick,” said Mr Trump.
North Carolina lawmaker Mark Meadows is being tipped by the Washington rumour mill as a replacement for Mr Mulvaney.
Mr Meadows, who is retiring from the House of Representatives where he led the hardline conservative Freedom Caucus, travelled with Mr Trump on Air Force One on Friday.
At a rare White House press conference in October, Mr Mulvaney appeared to implicate the president in an alleged corrupt deal with Ukraine.
The acting chief of staff told stunned reporters: “We do that all the time.” Mr Trump was reportedly outraged by the gaffe.
Mr Mulvaney then walked back his comments in a written statement that said: “Let me be clear, there was absolutely no quid pro quo between Ukrainian military aid and any investigation into the 2016 election.”
Who else is on the way out?
Former Illinois congressman Joe Walsh, one of the two long-shot challengers to Mr Trump for the Republican presidential nomination, announced on Friday that he is ending his campaign.
Mr Walsh, who received just 1% of the vote in Monday’s Iowa caucus, told CNN the modern Republican party “has become a cult”.
“I want to stop Trump. I believe he’s a threat to this country. He can’t be stopped within the Republican Party. Nobody can beat him.”
Bill Weld, former governor of Massachusetts, is now the only remaining Republican seeking to oust Mr Trump, who will seek re-election in November.