It is a major development in the U.S. election race.

President Joe Biden confirms he is not seeking re-election in a letter posted to X on his official account.

“It has been the greatest honour of my life to serve as your president,” the announcement said.

Biden says he will speak to the nation later this week in more detail.

It comes after a horrific performance in a debate with Republican nominee Donald Trump and growing calls for him to step aside.

“I have decided not to accept the nomination and to focus all my energies on my duties as President for the remainder of my term,” Biden said in a statement. “My very first decision as the party nominee in 2020 was to pick Kamala Harris as my Vice President. I want to offer my full support and endorsement for Kamala to be the nominee of our party this year.”

Biden is 81 and has been recovering since becoming sick with COVID.