Warren accused Sanders of calling her a liar, recording shows

Elizabeth Warren accused rival Bernie Sanders of calling her a liar at the end of a Democratic candidates' TV debate, according to a newly released recording.

On Tuesday, she refused to shake his hand during a tense, post-debate talk.

The audio of their heated exchange has since emerged, revealing what the candidates said to each other.

The progressive candidates for the presidential nomination had previously refused to attack each other.

On Monday, Ms Warren alleged Mr Sanders had told her in December 2018 that a woman could not win the presidency - something Mr Sanders denies.

Asked about this during Tuesday's debate in Des Moines, Iowa, Mr Sanders denied it again - saying he had long supported the idea of a female president.

They appeared to end the night on a tense, frosty exchange, which could not be heard on the live broadcast at the time. But sound of the moment was caught by CNN's back-up audio system and found later on Wednesday.

Here's the full exchange:

Ms Warren: "I think you called me a liar on national TV."

Mr Sanders: "What?"

Ms Warren: "I think you called me a liar on national TV."

Mr Sanders: "You know, let's not do it right now. If you want to have that discussion, we'll have that discussion."

Ms Warren: "Anytime."

Mr Sanders: "You called me a liar... You told me... [Tom Steyer interrupts]

Mr Sanders: "All right, let's not do it now."

Professional lip-readers can stand down. There's actual audio of the heated conversation that took place between Elizabeth Warren and Bernie Sanders after Tuesday night's debate. The curt back-and-forth between the two senators will make it difficult for the campaigns to play down the tensions in the days ahead.

Loyal volunteers, worn down from the grinding, door-to-door politicking in Iowa and New Hampshire, could let their tempers flare. In the hours after Tuesday night's debate, for instance, Sanders supporters took to social media to post snake pictures and emojis - suggesting duplicity - on Warren's accounts.

Many on the Sanders side insist Warren's move was a calculated betrayal, and even the post-debate confrontation - done with the cameras still running - was part of that plot.

Warren's supporters say that the Sanders team fired the first shot, distributing talking points to campaign workers that included derogatory information about Warren.

Whatever the cause, the unstated non-aggression pact between the two most liberal candidates is in tatters just weeks before the Iowa caucuses, whose unique format will pit the campaigns against each other in the most intimate kind of political conflict.

That is not a recipe for reconciliation.

Aides to the two candidates have for days attempted to de-escalate the feud amid fears that it could ultimately hurt them both and benefit more centrist Democratic hopefuls such as former Vice-President Joe Biden, the Associated Press reports.

This was the final televised debate for Democrats hoping to be nominated as their party's candidate to run for the US presidency.

The Iowa caucuses on 3 February kick off the presidential primary season, as the candidates battle for the right to challenge President Donald Trump in November's election.