DEMOCRATS are discussing replacing Joe Biden as their candidate in the US presidential race after an embarrassing performance in a TV debate with Donald Trump.

The US president appeared confused and tired throughout the debate with his Republican rival, underlining concerns about his cognitive state.

Andrew Yang, who ran for the Democrat nomination for president in 2020, called on Biden to step aside.

He tweeted: “Guys, the Dems should nominate someone else – before it’s too late. #swapJoeout.”

Speaking on TV after the debate, CNN’s chief national correspondent John King said: “This was a game-changing debate in the sense that right now as we speak there is a deep, a wide and a very aggressive panic in the Democratic Party.

“It started minutes into the debate and it continues right now. It involves party strategists, it involves officials, it involves fundraisers and they’re having conversations about the president’s performance, which they think was dismal, which they think will hurt other people down the party in the ticket.

“They’re having conversations about what they should do about it. Some of those conversations include should we go to the White House and ask the president to step aside. Other of the conversations are about should prominent Democrats go public with that call because they feel this debate was so terrible.”

David Plouffe, a former senior adviser to Barack Obama, described the debate as a “Defcon 1 moment”.

However, allies have stood by Biden, including his deputy Kamala Harris (above), the vice president.

Speaking after the debate, she said: “Yes, there was a slow start, but it was a strong finish.”

First lady Jill Biden (below) congratulated her husband after the head-to-head, saying: “Joe, you did such a great job.

“You answered every question! You knew all the facts!”

And Trump faced criticism for repeatedly lying during the debate, with American media firing out fact checks on his claims about immigration and his supporters’ riot following his defeat in the aftermath of the 2020 election, widely seen as an attempt to overrule the result.

Defending his performance amid calls to drop out of the race, Biden told reporters: “No, it’s hard to debate a liar. New York Times pointed out he lied 26 times, big lies.”

The 81-year-old has shown signs of mental decline in recent years, including displaying erratic behaviour at political events.

At a recent G7 meeting, Italian prime minister Giorgia Meloni guided Biden back to the group of world leaders after he appeared to wander off to give parachuters a thumbs up while the rest of the group faced the other way.

A clip of the incident forced the White House to issue a statement explaining the president’s actions.

Like the 78-year-old Trump (above), the Democrat candidate is given to rambling statements in public appearances.

According to a flash poll after Thursday’s debate, 67% of registered voters said that Trump won the debate compared with just 33% who thought Biden came out on top.

A UK-based Democrat supporters group conceded the debate was “not Biden’s best moment” but said they were standing by their candidate.