American Vice President Kamala Harris has lauded President Joe Biden for stepping down and endorsing her to be Democrats presidential candidate, vowing to defeat former President Donald Trump in the November presidential poll.

“I will do everything in my power to unite the Democratic Party—and unite our nation—to defeat Donald Trump and his extreme Project 2025 agenda” Mrs Harris wrote on X shortly after Mr Biden endorsed her on Sunday. “If you’re with me, add a donation right now.”

She added, “On behalf of the American people, I thank Joe Biden for his extraordinary leadership as President of the United States and for his decades of service to our country. I am honoured to have the President’s endorsement and my intention is to earn and win this nomination.”

Mr Biden, 81, bowed to pressure from his party, announcing on Sunday that he was quitting the race.

Calls for Mr Biden’s resignation had intensified following a lacklustre performance in a June debate against Mr Trump, during which Mr Biden appeared disoriented and made incoherent statements.

A week later at the NATO summit, Mr Biden made embarrassing gaffes, mistakenly referring to Mrs Kamala Harris as Mr Trump and confusing Ukrainian President Volodymyr Zelensky with Russian leader Vladimir Putin.

Meanwhile, Mr Trump emerged as the Republican Party’s presidential candidate at their National Convention last week. He has also selected David James Vance, a senator from Ohio, as his running mate for the 5 November election.