President-elect Biden, set to be inaugurated in January, previously served as vice president under Obama from 2009 to 2017. The pair are famously close friends, with Biden last year tweeting a picture of a friendship bracelet captioned “Happy #BestFriendsDay to my friend, @BarackObama.”
But a fellow democrat, as reported by Politico, recalled Obama stating: “Don’t underestimate Joe’s ability to f**k things up.”
Politico adds that Obama told another 2020 candidate of his close bond with the electorate in Iowa which he no longer has.
He is said to have also pointed out: “And you know who really doesn’t have it? Joe Biden.”
Various officials of the Obama administration and former aides, such as former chief strategist David Axelrod, have been critical of Biden’s campaign.
In April, Obama endorsed Biden in a 12-minute video on Twitter, saying: “Choosing Joe to be my Vice President was one of the best decisions I ever made, and he became a close friend.
“And I believe Joe has all the qualities we need in a President right now.”
A new Gallup poll has shown that support for Biden has risen six points to 55 percent, Newsweek reports.
Meanwhile support for Donald Trump has dropped to 42 percent.
Biden is recovering from a hairline fracture in his right foot after falling over while playing with his dog over the weekend.
X-rays of the 78-year-old’s foot were said to be “reassuring” with “no obvious” fracture.
He will be the oldest person in American history to become the US President when he takes office.
Donald Trump, 74, nicknamed Biden ‘Sleepy Joe’ in their hard-fought election campaign – suggesting he is too old to be president.
A doctor’s report in December revealed the president-elect takes statin tablets to maintain healthy cholesterol levels.
Mr Biden has warned Britain not to allow a hard border to be established between Northern Ireland and Ireland as a result of Brexit.
He has also suggested a post-Brexit trade deal between the US and Britain would be affected if this were to happen.
He told reporters: “We do not want a guarded border. We want to make sure – we’ve worked too long to get Ireland worked out, and I talked with the British prime minister, I talked with the Taoiseach, I talked with others, I talked to the French.
“The idea of having a border north and south once again being closed is just not right, we’ve just got to keep the border open.”
Speaking to Express.co.uk on Sunday, Amy Pope, former Deputy Homeland Security Adviser, said a no-deal Brexit would affect US-UK relations going forward.
Ms Pope said: “For many decades, the UK has been a bridge between the US and the rest of Europe – sharing a point of view when it comes to information and intelligence sharing, defence and security.
“That position has been upended as a result of the UK’s decision to leave the EU and it is clear the UK will have less strategic importance to the United States as a result.”