Sen. Bernie Sanders joined a rally in front of the White House on Tuesday night to speak out against the Dakota Access Pipeline project and he had a message for the new president-elect.

Sanders said Donald Trump "wants this country to become more dependent on fossil fuels."

"What we have to tell Mr. Trump and everybody else: We are not going silently into the night," he said. "The stakes are too high for the future of this planet."

As part of an unannounced stop at the rally that started earlier in the day at the U.S. Army Corps of Engineers office, Sanders spoke in front of the crowd and demanded the crude oil pipeline not be built.

Part of the 1,170-mile pipeline would cross the Missouri River near the Standing Rock Sioux Reservation in North Dakota, where indigenous people, environmentalists and activists say the pipeline will cross through sacred land and endanger the water supply.

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Sanders mentioned the hundreds of pipeline protests that took place around the world Tuesday. He also spoke about climate change, alternative energy options and President-elect Donald Trump's crippling plans for the environment.

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Actress Shailene Woodley, who was arrested earlier this year at Standing Rock, livestreamed the demonstration in front of the White House, including Bernie's appearance and impromptu speech.

The U.S. Army Corps of Engineers recently called for more time to review pipeline construction plans near the Standing Rock Sioux Tribe lands, meaning a delay in construction and a temporary and small win for protesters.