U.S. Ambassador William Hagerty will leave his post to run for the Senate, President Donald Trump tweeted late Friday from Washington, garnering a "Complete & Total Endorsement" from the American leader.

"Tennessee loving Bill Hagerty, who was my Tennessee Victo(r)y Chair and is now the very outstanding Ambassador to Japan, will be running for the U.S. Senate," Trump tweeted. "He is strong on crime, borders & our 2nd A. Loves our Military & our Vets. Has my Complete & Total Endorsement!"

The announcement, which could not immediately be confirmed by Hagerty's office, comes at a time when Japan, a top U.S. ally, is embroiled in a heated trade and history-related row with South Korea, another key American partner in the region.