Hillary Clinton says 'nobody likes' Bernie Sanders as she refuses to say if she would endorse him as a Democratic nominee

Hillary Clinton dismissed Bernie Sanders as a "career politician" who "nobody likes" in a scathing attack on her 2016 rival as she weighed into the Democratic presidential nomination race.

Mrs Clinton, the Democrats' presidential candidate in 2016, also declined to commit to backing Mr Sanders if he wins the race to take on Donald Trump this November.

The barbed remarks, made in a Hulu documentary, come just before the first votes are cast in the Democratic primaries on February 3.

"He was in Congress for years. He had one senator support him. Nobody likes him, nobody wants to work with him, he got nothing done. He was a career politician. It's all just baloney and I feel so bad that people got sucked into it," Mrs Clinton says in the documentary, according to The Hollywood Reporter.

It underscores the lingering bitterness Mrs Clinton has towards Mr Sanders, who launched an unexpected challenge against her presidential nomination in 2016.

Mrs Clinton's backers blame Mr Sanders' supporters for tarnishing her with vitriolic criticism, saying it helped put her Republican rival Mr Trump in the White House.

Mrs Clinton also waded into the dispute between Mr Sanders and his rival for the 2020 presidential nomination Elizabeth Warren, saying the Vermont senator's campaign had demonstrated "a pattern" of attacking female rivals.

"This argument about whether or not or when he did or didn't say that a woman couldn't be elected, it's part of a pattern," Mrs Clinton told the Hollywood Reporter.

"If it were a one-off, you might say, 'OK, fine'. But he said I was unqualified. I had a lot more experience than he did, and got a lot more done than he had, but that was his attack on me."

Mr Sanders and Ms Warren, the two most progressive candidates in the Democratic contest, are currently in second and third place in national polls respectively. Joe Biden, the former US vice president, is in first place.

Mrs Clinton refused to say whether she would endorse Mr Sanders should he win the nomination this year, citing the competitive Democratic field, but she characterised his campaign as having a culture of insult and attack.

"I really hope people are paying attention to that because it should be worrisome that he has permitted this culture — not only permitted, [he] seems to really be very much supporting it," she told the Hollywood Reporter.

Asked about the remarks, Mr Sanders responded: “My focus today is on a monumental moment in American history: the impeachment trial of Donald Trump. Together, we are going to go forward and defeat the most dangerous president in American history.”

The four-part documentary, "Hillary",  will premiere at the Sundance Film Festival.