Rep. Alexandria Ocasio-Cortez accepted a $2,700 donation from billionaire Tom Steyer, who is running as a Democrat for president, according to a 2018 filing uncovered by OpenSecrets.org.

The donation comes after Ocasio-Cortez railed against billionaire money in politics during a campaign event for Sen. Bernie Sanders last week. "For anyone who accuses us for instituting purity tests — it's called having values," she said. "It's called giving a damn. It's called having standards for your conduct to not be funded by billionaires but to be funded by the people."

The long-simmering tension between Democratic hopefuls boiled over at the sixth Democratic debate in Los Angeles in December, with Buttigieg and Warren arguing over their donor base and personal wealth. As the Democratic Party attempts to coax working-class voters, candidates have tried to diminish the role that big money plays in their campaigns.

"According to Forbes magazine, I'm literally the only person on this stage who's not a millionaire or a billionaire," Buttigieg said.

"We made the decision many years ago that rich people in smoke-filled rooms would not pick the next president of the United States," Warren fired back. "Billionaires in wine caves shouldn't pick the next president of the United States."

The in-fighting over money has allowed Sanders to pick up major endorsements from the liberal wing of the Democratic Party during the past month. Ocasio-Cortez joined Rep. Ilhan Omar in endorsing Sanders for president in December.

"I do think a system that allows billionaires to exist when there are parts of Alabama where people are still getting ringworm because they don't have access to public health is wrong," Ocasio-Cortez said at the Martin Luther King forum in New York City earlier this year.

Steyer and former New York City Mayor Michael Bloomberg have been dogged by criticism that they bought their way into the race. According to Politico, the two candidates have already spent more than $200 million in TV and radio campaign ads.