Senator Bernie Sanders has quit the presidential race, clearing the way for Joe Biden to take on Donald Trump in the November election.
The two politicians, who had spent the last year battling for the Democratic nomination, appeared to put on a united front on Monday.
They appeared together by split-screen on Biden's livecast, where he appealed to all Americans to unite to defeat Trump.
Sanders urged the voters "to come together in this campaign to support (Biden's) candidacy, which I endorse, to make certain that we defeat somebody who I believe ... is the most dangerous president in the modern history of this country."
He put up a united front, telling voters that "it's imperative that all of us work together."
Before the Democratic primary contest was halted due to the pandemic, Biden had secured a commanding edge over Sanders.
Israel strikes Yemen airport as WHO chief boards plane
Syria's new rulers declare crackdown as tensions flare in coastal area
Manmohan Singh, India's reluctant prime minister, dies aged 92
Russian air defence downed Azerbaijan Airlines plane: Sources
Thousands mark 20 years after deadly Indian Ocean tsunami
