Barack Obama has said Donald Trump's refusal to accept the results of the election that delivered victory for Democrat Joe Biden is putting the United States on a "dangerous path".

Mr Trump is trying to convince the people that they should not believe the numbers that clearly demonstrate his rival's win.

Rather, he is making baseless claims of massive fraud, demanding recounts and calling for audits in an effort to discredit the outcome and, in the process, put democracy itself on trial.

Mr Obama, who invited Mr Trump to the White House soon after his election win four years ago and pledged co-operation in the transfer of power, said he is not shocked that a man who "never admits loss" is refusing to acknowledge defeat now.

"I'm more troubled by the fact that other Republican officials, who clearly know better, are going along with this, are humouring him in this fashion," Mr Obama told CBS show 60 Minutes.

"It is one more step in delegitimising not just the incoming Biden administration but democracy generally. And that's a dangerous path."

His comments come as Mr Trump worked to take back an apparent acknowledgment that Mr Biden won the White House and was making clear he would keep trying to overturn the election result.

Mr Trump's earlier comments on Sunday had given some critics and supporters hope that the White House was ready to begin working on a transition with Mr Biden's team.

Mr Trump, without using Mr Biden's name, said that "He won" as part of a tweet that made baseless claims about a "rigged" election.

But as the Republican president saw how his comments were being interpreted as his first public acknowledgment of a Biden victory, he quickly reversed course.

"He only won in the eyes of the FAKE NEWS MEDIA," Mr Trump subsequently tweeted. "I concede NOTHING! We have a long way to go. This was a RIGGED ELECTION!"

There was no widespread fraud in the 2020 election.

In fact, election officials from both political parties stated publicly that the election went well, and international observers confirmed there were no serious irregularities.

Mr Trump's campaign has tried to mount legal challenges across the country, but many of the lawsuits have been thrown out and none has included any evidence that the outcome might be reversed.

Mr Biden defeated Mr Trump by winning back a trio of battleground states: Michigan, Wisconsin and Pennsylvania, and topped the 270 electoral vote threshold to clinch the presidency.

He so far has 78.8 million votes, the most ever by a winning candidate, to Mr Trump's 73.1 million.

Nearly two weeks after Election Day, Mr Trump has neither called Mr Biden nor made a formal concession, and White House officials have insisted that they are preparing for a second term.