LOS ANGELES — Bernie Sanders escalated his rhetoric in his populist 2020 Democratic presidential primary campaign, swiping at rival Pete Buttigieg's "wine cave" fundraiser.

"Our campaign has received more contributions from more people than any candidate in the history of the United States of America," Sanders, 78, told a crowd gathered Saturday in Los Angeles.

The socialist Vermont senator, the Democratic runner-up to 2016 nominee Hillary Clinton, picked up on a line used by another 2020 Democrat, Massachusetts Sen. Elizabeth Warren, at the party's debate Thursday.

"We don't have a super PAC," Sanders said. "We don't want a super PAC. We don't go to rich people's wine caves. This is a campaign of the working class of this country, by the working class, and for the working class."

Buttigieg, 37, was a political punching bag during the debate after photos emerged of a recent fundraiser from a Napa Valley winery. The South Bend, Indiana, mayor, who is vying for the nomination from a center-left lane, compared to Sanders's far-left platform, was photographed talking to donors in a wine cellar underneath a chandelier boasting 1,500 Swarovski crystals.

Earlier in the rally, New York Rep. Alexandria Ocasio Cortez, who has endorsed Sanders, slammed Buttigieg indirectly for criticizing Warren for holding her competitors to so-called primary "purity tests."

"It's called having values," she said.

Buttigieg spokesman Sean Savett pushed back on the pair's attacks, citing how the mayor's average contribution for 2019's third financial quarter was $32, with 98% of his donations coming in at under $200.

“We're proud to be running a campaign that's powered by more than 700,000 grassroots donors from across the country — and the only promise any donor will ever get from Pete is that he'll use that money to defeat Donald Trump," Savett told the Washington Examiner.

Sanders is proving resilient against opponents such as Buttigieg, Warren, and former Vice President Joe Biden. Though he suffered a heart attack two months ago, the RealClearPolitics national polling average Saturday has Sanders at 19.3%, in second place behind Biden's 27.8%.

Sanders on Saturday touted some of his key policy proposals before the friendly audience, including "Medicare for all," which has become a wedge issue among the top-tier contenders.

"We're going to take on the Republican Party. We're going to take on the Democratic establishment," Sanders said. "This status quo is not working."