US President Joe Biden has withdrawn from his bid for re-election, saying it is “in the best interest of my party and the country for me to stand down”.

Mr Biden has also offered his “full support” to Vice President Kamala Harris to be the Democrat nominee.

In a post on his social media account, he said: “My fellow Democrats, 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.

“My very first decision as the party nominee in 2020 was to pick Kamala Harris as my Vice President. And it’s been the best decision I’ve made. Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year. Democrats — it’s time to come together and beat Trump. Let’s do this.”

In a separate letter posted to X, Mr Biden said it had been the greatest honour of his life to serve as president.

“And while it has been my intention to seek re-election, 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 the duties as President for the remainder of my term.”

He said in his statement he would address the nation on the matter next week, adding: “For now, let me express my deepest gratitude to all those who have worked so hard to see me reelected. I want to thank Vice President Kamala Harris for being an extraordinary partner in all this work. And let me express my heartfelt appreciation to the American people for the faith and trust you have placed in me.

“I believe today what I always have: that there is nothing America can’t do – when we do it together. We just have to remember we are the United States of America.”

The decision comes after escalating pressure from Mr Biden’s Democratic allies to step aside following his faltering June 27 debate.

Mr Biden’s term in office ends at noon on January 20 2025.

Writing on his Truth Social platform, former US president Donald Trump, who is standing for the Republican Party, said: “Joe Biden was not fit to run for President, and is certainly not fit to serve – And never was!”

He added: “We will suffer greatly because of his presidency, but we will remedy the damage he has done very quickly. MAKE AMERICA GREAT AGAIN!”

In response to Mr Biden’s statement, Reform UK leader Nigel Farage said: “I predicted this would happen in September 2023.

“Whoever they pick, Trump will win in November.”