Adam Schiff, a prominent House Democrat, has asked incumbent U.S. President Joe Biden to drop out of the presidential race, citing serious doubt over the president’s chances of winning.

“Mr Biden has been one of the most consequential presidents in our nation’s history, and his lifetime of service as a senator, a vice president and now as president has made our country better.

“A second Trump presidency will undermine the very foundation of our democracy, and I have serious concerns about whether the president can defeat Donald Trump in November,” he told The Los Angeles Times in a statement.

At a private meeting with donors, Mr Shriff, who is running for Senate, said that if Mr Biden remained the party’s nominee, Democrats were likely to lose not only the White House but also down-ballot races.

However, the congressman’s public statement has been considered a significant escalation.

Mr Shriff, who opposed Mr Biden’s ambition to retain the office, noted that he would support the Democratic ticket, even if the incumbent president stayed at the top.

Although, he believed it would be better for Mr Biden to “pass the torch.”

While other critics have suggested that Mr Biden stepped down from the race, Mr Schiff’s statement again brings the number of Democrats who have called on the president to end his campaign to at least 20.

Mr Biden recently said only the “Lord Almighty” can convince him to quit his re-election bid.