Alexander Vindman, who accused Mr Trump of “improper” conduct, is expected to leave the White House.

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US President Donald Trump says he is “not happy” with a White House aide who is expected to be removed after he testified in the impeachment hearings.
Lt Colonel Alexander Vindman is leaving the National Security Council (NSC) for the Pentagon, according to sources.
But the president denied reports that his Acting Chief of Staff Mick Mulvaney is also for the chopping block.
Mr Trump is said to desire a staff shake-up after senators cleared him in the impeachment case on Wednesday.
What next for Alexander Vindman?
“I’m not happy with him [Lt Col Vindman],” said the president. “You think I’m supposed to be happy with him? I’m not.”
“They’ll make that decision,” Mr Trump told reporters as he left the White House for North Carolina on Friday, in a possible reference to Lt Col Vindman’s senior US Army officers.
The president added that his impeachment should be erased from the congressional record.
Media captionLt Col Vindman testified in November about the president’s “improper” call
According to White House sources, Lt Col Vindman had expected a transfer. He has been telling colleagues for weeks that he is ready to move to back to the defence department, where he still holds active-duty soldier status.
But Lt Col Vindman was still working at the White House on Friday.
On Friday, US Defence Minister Mark Esper told reporters: “We welcome back all of our service members, wherever they served, to any assignment they’re given.
“And as I said we protect all of our service members from retribution or anything like that.”
What next for Mick Mulvaney?
In his comments to the press, Mr Trump also 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.
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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.”
How did Vindman annoy Trump?
Lt Col Vindman is a Ukraine expert who 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. Democratic lawmakers argued 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, he answered: “Congressman, because this is America… and here, right matters.”