evidence: US President Joe Biden has ended his re-election campaign and 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. [...] In the wake of Mr Biden's decision, he declared the president "was not fit to run... and is certainly not fit to serve". Other senior Republicans joined him in their criticism, and called on Mr Biden to leave the White House immediately, not just the Democratic candidacy. [...] - LIVE: Latest updates as Joe Biden drops out of US presidential election race - WATCH: How Joe Biden's bid for re-election came to an end - IN FULL: Biden's letter announcing his withdrawal - PROFILE: Kamala Harris, the VP who Biden is backing for president - EXPLAINED: Biden has endorsed Harris. What happens next?