Story highlights "Secretary Clinton owes us an apology. We were not lying," Sanders said

"Secretary Clinton has relied heavily on funds from lobbyists working for the oil, gas and coal industry," he added

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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