Sheboygan, Wisconsin(CNN) In an unusually direct move, Sen. Bernie Sanders on Friday called on Hillary Clinton to apologize to him for saying that his campaign is lying about her relationship with fossil fuel money.
"Secretary Clinton owes us an apology. We were not lying. We were telling the truth," the Vermont senator said during a standard section of his stump speech here.
Sanders was referring to a video released Thursday that shows Clinton angrily responding to an activist affiliated with Greenpeace and 350 Action, two climate organizations, who asked Clinton if she will "reject fossil fuel money" from her campaign.
"I do not have, I have money from people who work for fossil fuel companies," Clinton said. "I'm so sick. I'm so sick of the Sanders' campaign lying about me. I'm sick of it."
Sanders countered her remarks Friday.
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"The truth is that Secretary Clinton has relied heavily on funds from lobbyists working for the oil, gas and coal industry. According to an analysis done by Greenpeace, Hillary Clinton's campaign and her super PAC have received more than $4.5 million from the fossil fuel industry," he said.
He added: "In fact, 57 oil gas and coal industry lobbyists have directly contributed to her campaign, with 43 of them contributing the maximum allowed for the primary. And these are not just workers in the fossil fuel industry, these are paid, registered lobbyists."
Clinton's 2016 campaign has taken more than $300,000 from people who work for those companies, according to Greenpeace. Clinton's campaign said Thursday that Sanders has taken upwards of $50,000 from the same individuals.
Michael Briggs, a spokesman for the Sanders campaign, said the issue isn't about individual employees but rather "lobbyists and bundlers for the industry."
"We have not accused Senator Sanders of being beholden to the oil and gas industry on that basis, nor should he say that of Hillary Clinton," said Brian Fallon, Clinton's press secretary.