Gorbachev calls Trump's withdrawal from arms treaty 'a mistake'
Trump's personal assistant John McEntee fired from role: report
John McEntee on Monday was escorted out of the White House, according to two senior administration officials.
He was escorted from the White House because of an "unspecified security issue," the Journal reported, citing a third White House official.
The Trump campaign announced on Tuesday that McEntee is rejoining the campaign as a senior adviser.
White House press secretary Sarah Huckabee Sanders told the Journal that "we don't comment on personnel issues."
According to the Journal, it is not clear why McEntee was fired.
"It's not going to be great for morale," one White House official said about his leaving.
McEntee has been working with Trump since the early days of his presidential campaign.
In his role in the White House, McEntee did tasks such as giving the president messages and making sure the clocks were correctly set for daylight saving time.
According to the Journal, he was not allowed to gather his belongings before being escorted out of the White House.