Turning to Warren, Phillip asked a question whose premise was that she didn't believe Sanders - a rare implied rebuke of a major presidential candidate by a debate moderator. As she is refusing his extended hand, Warren repeats, "I think you called me a liar on national TV".
"I think you called me a liar on national TV", she told him.
Sanders: "You called me a liar".More news: Kim Kardashian Packs Into Barely There Pink Bikini, "About To Pop Out"
"Do you want to have this discussion?" "You told me-" he said, before cutting himself off and saying, "Alright, let's not do it now". "You told me - all right, let's not do it now".
Meanwhile, Tom Steyer, caught awkwardly between the longtime friends and colleagues, said: "I don't want to get in the middle".
The Vermont senator denies having made the comments, and last night in Wisconsin, Donald Trump took the time to side with Sanders. It was an odd moment: Phillip, a veteran of the Washington Post, ABC News and Politico, was appearing to dismiss Sanders' denial or imply that it was not believable.
'Hillary Clinton won the popular vote by three million votes. "Look at the men on the stage - collectively they've lost 10 elections", she added.More news: Canadian Rocky "Soul Man" Johnson, father of Dwayne "The Rock" Johnson dies
For those on stage, the debate offered the candidates a final high-stakes chance to make their case to voters. Sanders later added, "Anybody knows me knows that it's incomprehensible that I would think that a woman can not be president of the United States..." But, look, this question about whether or not a woman can be president has been raised and it's time for us to attack it head-on'.
Warren's and Sanders' aides have for days attempted to de-escalate the feud as some progressives worry that ill will between the cause's two leading voices will ultimately hurt both of them and could benefit more moderate Democratic presidential hopefuls like former Vice President Joe Biden and former South Bend, Indiana, Mayor Pete Buttigieg.
Biden, a former chairman of the Senate Foreign Relations Committee who touts his security credentials, acknowledged the vote "was a big, big mistake" and said that as President Barack Obama's vice president, he worked to bring the troops home.
Warren continued: 'And the only person on this stage who has beaten an incumbent Republican anytime in the past 30 years is me.More news: U.S. stocks end mixed amid solid earnings, lacklustre CPI data