On Thursday, Democratic presidential front-runner Hillary Clinton accused the campaign of her opponent Sen. Bernie Sanders (I-VT) of lying about her in a a video posted by environmental activist group Greenpeace.

“I am so sick of the Sanders campaign lying about me. I’m sick of it,” Clinton said.

Clinton’s reaction was inspired by a question directed to her about taking donations from the fossil fuel industry and if whether or not she would reject their campaign contributions in the future.

Clinton in the past has been confronted by environmental activist during this election season. Back in February, she downplayed a $150,000 donation she received from fossil fuel interests.

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