24 former democratic members of the US Congress are urging Joe Biden to step aside in a letter.
At the same time, nearly 20 active politicians within the party have now done the same.
Two dozen former politically active Democrats, including a former senator and several with long experience, want to see another presidential candidate than Joe Biden in the election in November.
In a joint letter that Politico has taken part of, they emphasize that they do not doubt Biden's "extraordinary merits" – but also warn that the Democrats will likely lose in the autumn presidential election with Biden as a candidate.
Want to see other candidates
In the letter, they write that Biden "would best serve the country he loves" by allowing the convention delegates who have committed to voting for him at the Democratic Convention – which would make him the party's official candidate – to instead vote for others.
"We are confident that one or more competent Democratic candidates would step forward. Enthusiasm and optimism would follow", write the 24 former members in the letter.
The letter is the latest in a series of events that have increased the pressure on Biden, since his disastrous performance in a TV debate against Donald Trump. Critical voices are questioning whether the 81-year-old president has the capacity to manage four more years in the White House.
"Pass the torch"
Since last week's NATO summit and subsequent press conference, where Biden made some notable mistakes, five of the Democrats' members of the House of Representatives have urged Biden to step aside.
"It's time for President Biden to pass the torch", says Mike Levin, California, in a statement.
In total, 19 of the Democrats' 213 members of the House of Representatives have now directed the same appeal to Biden.