Updated 3:18 p.m. | White House Counsel Don McGahn will leave his post this fall following the expected confirmation of Supreme Court nominee Brett Kavanaugh, President Donald Trump announced Wednesday.

The president used a tweet the make the announcement, which comes amid Special Counsel Robert Mueller’s ongoing investigation into Russian election meddling and possible illegal coordination with Trump’s 2016 presidential campaign.

“I have worked with Don for a long time and truly appreciate his service!” the president’s tweet said.

The announcement drew attention from Iowa Republican Sen. Charles E. Grassley.

“I hope it’s not true McGahn is leaving WhiteHouse Counsel. U can’t let that happen,” the Judiciary chairman tweeted.

@realDonaldTrump I hope it’s not true McGahn is leaving WhiteHouse Counsel. U can’t let that happen

— ChuckGrassley (@ChuckGrassley) August 29, 2018

Judiciary Committee Republicans have joined their Democratic colleagues in urging the president to avoid any moves that would be considered him moving to directly interfere with or end the special counsel probe.

The announcement of McGahn’s departure comes weeks after the revelation that he recently was interviewed by Mueller and his team for more than one full day.

Trump contends he signed off on the testimony; George W. Bush-era White House counsel and attorney general Alberto Gonzales, however, told CNN Monday morning that a sitting White House counsel would be required to fully cooperate with a federal investigation because he is a government lawyer, not a president’s personal attorney.

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But Trump on Aug. 20 tweeted that McGahn spoke with the special counsel team for “over 30 hours with the White House Councel [sic], only with my approval, for purposes of transparency.”

The length of the Mueller-McGahn sessions led Trump to the conclusion the special counsel is “looking for trouble” because they “they know there is no Russian Collusion.”

“Not at all,” Trump told reporters Wednesday when asked if McGahn’s testimony concerned him and led to the White House counsel’s coming departure. “He’s done an excellent job.”

He also said he has great “affection” for McGhan and predicted he will “do very well” when he heads to, likely, the private sector.

White House press secretary Sarah Huckabee Sanders said there is “really not” a major reason McGahn is leaving this fall. “He’s worked for the president for a long time. He’s been – they have a good relationship. There’s really not a lot to add here,” she said.

In May, Trump replaced Ty Cobb as the White House’s top attorney handling the Mueller probe with Clinton impeachment lawyer and George W. Bush White House veteran Emmet Flood. The McGahn announcement raised immediate questions at the White House about whether Flood might become White House counsel.

“People like him. He’s super well-respected around the building,” Sanders said of Flood. “But there’s not a plan locked in place at this point.”

McGahn once refused an order from Trump to fire Mueller, instead telling the president he would quit if the former FBI chief was dismissed.

The departing chief White House lawyer was the top attorney on Trump’s 2016 campaign. Before that, he was a GOP campaign finance lawyer and Federal Election Commission member.