Former Democratic presidential candidate Hillary Clinton shifted blame for her loss against President Trump in the 2016 general election to Sen. Bernie Sanders.

"There was no question about who was going to be the nominee," Clinton said in an interview last week. "But unfortunately, you know, his campaign and his principal supporters were just very difficult and really, constantly not just attacking me but my supporters ... it had an impact."

Clinton won the 2016 Democratic nomination for president following an acrimonious convention in which Sanders supporters loudly voiced displeasure with the former secretary of state.

Sanders is again running for president in 2020, and recent polling shows him surging ahead of front-runner Joe Biden in the early voting state of Iowa.

Clinton said during a forthcoming documentary series she believes Sanders is not likable enough to be elected president.

"He was in Congress for years," she said. "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."

The 2020 Iowa caucuses are set to take place on Monday.

[ Related: 'Cannot happen again': Hillary Clinton blames Bernie Sanders for disunity in Democratic Party]

