By Jeff Mason, Jarrett Renshaw and Kanishka Singh

WASHINGTON (Reuters) -U.S. President Joe Biden ended his reelection campaign on Sunday after fellow Democrats lost faith in his mental acuity and ability to beat Donald Trump, leaving the presidential race in uncharted territory.

Biden, in a post on X, said he will remain in his role as president and commander-in-chief until his term ends in January 2025 and will address the nation this week.

“It has been the greatest honor of my life to serve as your President. And while it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and to focus solely on fulfilling my duties as President for the remainder of my term,” Biden wrote.

By dropping his reelection bid, he clears the way for Vice President Kamala Harris to run at the top of the ticket, the first Black woman to do so in the country’s history.

Biden, 81, did not mention her when he announced his move.

It was unclear whether other senior Democrats would challenge Harris for the party’s nomination, who was widely seen as the pick for many party officials – or whether the party itself would choose to open the field for nominations.

Biden’s announcement follows a wave of public and private pressure from Democratic lawmakers and party officials to quit the race after his shockingly poor performance in a televised debate last month against Republican rival Donald Trump.