A top staffer for Sen. Bernie Sanders (I-VT) said Friday that Hillary Clinton owes her Democratic presidential rival an apology, after video circulated online of Clinton accusing the senator of lying about her taking money from fossil fuel companies.

“I think she probably owes the senator an apology for that because the senator is not lying about her record,” Sanders campaign manager Jeff Weaver said on MSNBC. “He’s talking about her record. He’s talking about her practices. She obviously doesn’t like it, but that doesn’t make it lying because you don’t like it.”

He went on to say campaign finance is one of the core issues Sanders is addressing on the campaign trail.

“What the Clinton campaign is cagey about – it doesn’t really wanna talk about – is the fact their super PAC gets money from people connected with fossil fuel industry,” Weaver said. “It is the lobbyists, it is the fact that they have lobbyists from the fossil fuel industry—just like they have lobbyists from the banking industry, the drug companies and frankly now we find out the gun lobby—who are giving them money, right, who are bundling this money and giving it to them.”

A Huffington Post analysis found “nearly all” of the lobbyists “bundling” campaign contributions for Clinton have ties to the fossil fuel industry.

Clinton was captured on video admonishing a Greenpeace activist after a Thursday campaign event in New York when asked about donations from the industry. “I’m so sick of the Sanders campaign lying about me. I’m sick of it,” Clinton said while wagging a finger at the woman.