White House counsel Don McGahn to quit

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.

McGahn's departure will be the latest in a large number of high-ranking officials to leave the Trump White House.