WASHINGTON, Aug. 29 (Xinhua) -- White House counsel Don McGahn will be leaving in fall, U.S. President Donald Trump announced Wednesday.
"I have worked with Don for a long time and truly appreciate his service," Trump said in a morning tweet.
McGahn's departure will follow a Senate vote on Judge Brett Kavanaugh's nomination to the Supreme Court, the president added.
McGahn, 50, has played a key role in Trump's overhaul of the federal judiciary with conservative judges, helping the president select Supreme Court Justice Neil Gorsuch and nominate Kavanaugh.
But the relationship between Trump and McGahn, who served as general counsel for Trump's campaign and transition team, has become strained over the ongoing Russia investigation.
Special counsel Robert Mueller is looking into the alleged Russian interference in the 2016 U.S. presidential election and any potential collusion between the Trump campaign and Moscow, among other matters that may arise from the investigation.
Trump has repeatedly attacked the probe by calling it a "hoax" or "witch hunt," raising long-running speculation that he would force it to be shut down, a move that analysts say could trigger a political firestorm.
McGahn threatened to resign last year if Trump continued to press for the removal of Mueller, while he reportedly held extensive talks with Mueller this month, which Trump said he had authorized.
The New York Times reported earlier this month that McGahn gave detailed accounts for the special counsel probe, including on the question of whether Trump obstructed justice by firing former FBI Director James Comey.
"I allowed White House Counsel Don McGahn, and all other requested members of the White House Staff, to fully cooperate with the Special Counsel," Trump tweeted in response to the report.
"In addition we readily gave over one million pages of documents. Most transparent in history. No Collusion, No Obstruction. Witch Hunt!" the president also said.
Republican Senator Chuck Grassley of Iowa on Wednesday pushed back on Trump's announcement that Don McGahn would leave, saying "I hope it's not true."
"U can't let that happen," tweeted Grassley, who chairs the Senate Judiciary Committee, the panel in charge of Kavanaugh's confirmation hearings, which are slated to kick off next month.
McGahn's departure will be the latest in a large number of high-ranking officials to leave the Trump White House.
The White House counsel is among the most critical - and yet least visible - positions within the West Wing.
Emmet Flood, who replaced Ty Cobb in May as the White House's top attorney handling the Mueller probe, has been considered a leading candidate for McGahn's post.
"People like him. He's super well-respected around the building," White House press secretary Sarah Huckabee said of Flood. "But there's not a plan locked in place at this point."