Barack Obama tells Democrats it's 'time to unite behind Hillary Clinton'

It was reported that Mr Obama was inspired by concerns about the success of Donald Trump's campaign

Mr Obama has reportedly told donors to unite behind a candidate (AP)

Bernie Sanders has said calls for him to drop out of the presidential race are "absurd" following reports President Barack Obama had called for Democrats to unite behind Hillary Clinton.

Mr Obama reportedly told Democratic donors that it is time for the party to unite behind Hillary Clinton - saying it was essential they came together to defeat the soaring candidacy of Republican frontrunner Donald Trump.

The president has been very careful not to be seen to favour either Ms Clinton, or her Democratic rival Mr Sanders as they have sought the nomination.

But as Ms Clinton has increasingly cemented her position and Mr Sanders’ dream of winning looks ever more likely, the New York Times said the president had urged donors to get ready for the general election.

Bernie Sanders has vowed to continue his campaign (AP)

The paper said that in “unusually candid remarks”, Mr Obama privately told a group of Democratic donors last Friday that Mr Sanders was nearing the point where his campaign would come to an end.

It said he acknowledged that Ms Clinton is perceived to have weaknesses as a candidate, and that some Democrats did not view her as authentic. But he is said to have played down the importance of authenticity, saying that President George Bush was once praised for his authenticity.

Mr Obama made the remarks after reporters had left a fund-raising event in Austin, Texas, for the Democratic National Committee, the newspaper said. Asked about this at the daily press briefing, White House spokesman Josh Earnest said Mr Obama has said the party needed to unite behind a candidate, but denied that he had said that should be Ms Clinton

His intervention in the nomination battle has come at a critical time for Mr Sanders. After the Vermont senator failed to win a single state in last Tuesday’s primary contests - Ms Clinton scooping all five states - his path to the nomination looks ever more difficult.

While he has vowed to fight on, insisting he still has a path to the presidency, he would need to win the remaining 70 per cent of remaining delegates.

Mr Sanders’ campaign manager, Jeff Weaver, and his senior campaign adviser, Tad Devine, told reporters on Wednesday that they believed he could catch Ms Clinton. They added that Mr Sanders expected to do very well in coming contests in Arizona, Wisconsin, Idaho, Utah, Washington and New York.

“We are literally about halfway through,” Mr Weaver said.

Mr Sanders said in a statement earlier this week: “With more than half the delegates yet to be chosen and a calendar that favours us in the weeks and months to come, we remain confident that our campaign is on a path to win the nomination.”