The spokesman for Sen. Bernie Sanders's (I-Vt.) 2016 presidential campaign slammed Hillary Clinton and her staff as "total ingrates" and "assholes" following criticism from ex-Clinton aides over Sanders's use of private jets.

"You can see why she's one of the most disliked politicians in America. She's not nice. Her people are not nice," Michael Briggs, the spokesman, told Politico of Clinton. "[Sanders] busted his tail to fly all over the country to talk about why it made sense to elect Hillary Clinton and the thanks that [we] get is this kind of petty stupid sniping a couple years after the fact."

Briggs also called Clinton and her staff "assholes."

"It doesn't make me feel good to feel this way but they're some of the biggest assholes in American politics," he said, according to Politico.

In the same Politico story, ex-Clinton aides were critical of Sanders reportedly making requests for him and his staff to use private jets while he served as a campaign surrogate for Clinton, the 2016 Democratic nominee. The Sanders team's reported preference for private jets was a point of tension with the Clinton campaign, according to Politico.

Rania Batrice, who was Sanders's deputy campaign manager during part of his 2016 campaign, denied to Politico that the campaign ever requested "a private plane for the sake of having a private plane."

Tensions between the Sanders and Clinton campaigns were high throughout the 2016 election cycle, before and after the two faced off for the Democratic nomination. Sanders is running again for the nomination in 2020.

Sanders spokesperson Arianna Jones told Politico that the flights were used to ensure Sanders "could get to as many locations as quickly as possible in the effort to help the Democratic ticket defeat Donald Trump."

"Sen. Sanders campaigned so aggressively for Secretary Clinton, at such a grueling pace, it became a story unto itself, setting the model for how a former opponent can support a nominee in a general election," Jones added.

Politico also reported that Sanders has continued to use private jets since that election, reportedly having spent at least $342,000 on those flights.