Western media reports say that just two days after announcing he was prepared to return to the campaign trail, US President Joe Biden yesterday announced that he is dropping out of the race, taking members of his staff by surprise.   

Mr. Biden has reportedly endorsed Vice-President Kamala Harris to succeed him as the Democratic candidate, in an extraordinary decision that upends an already dramatic race for the White House.

"It has been the greatest honor of my life to serve as your President," Biden said in part in his statement, according to ABC News.

The BBC reports that Mr. Biden, 81, said in a Sunday written statement that it was the “greatest honor” to serve but his withdrawal was in the best interest of my party and the country.”

The announcement reportedly caps a tumultuous period in US politics, which began with his sometimes incoherent debate performance against Donald Trump on June 27.  Mr. Biden says he will remain president until January.

Citing its sources, ABC News says Biden's decision came just eight days after Senate Democratic Leader Chuck Schumer visited Biden in his Rehoboth, Delaware, beach home and had a heart-to-heart talk with Biden about leaving the race.

ABC News notes that in a letter to the nation, Biden didn't elaborate on what thinking may have prompted his decision, saying only “And while it has been my intention to see 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.”

The BBC says Ms. Harris, 59, said that she was “honored” to be endorsed, adding she would “earn and win this nomination” and unite the country against Trump.

“We have 107 days until election day,” she said.  “Together, we will fight. And together, we will win.”

While Ms. Harris has been picking up endorsements from many big figures in the party, she is yet to be officially nominated, and that may not happen until the Democratic National Convention in August.

Mr. Donald Trump meanwhile has pulled ahead in polling and was confirmed as Republican nominee at the party's convention in Milwaukee last week, five days after surviving an assassination attempt.