Sen. Bernie Sanders (I-Vt.) voiced concerns Tuesday that President-elect Donald Trump is breaking a core campaign promise of keeping special interests out of Washington ― “draining the swamp.”

Sanders and Sen. Sheldon Whitehouse (D-R.I.) said on a call with reporters that they support Trump’s pledge to keep corporate interests out of Washington. “Bernie and I and many of our colleagues agree wholeheartedly with the president-elect on this sentiment,” Whitehouse said. “And we’ve been fighting in Congress to resist the corporate special-interest pressure that surrounds us.”

But Trump’s transition team, which includes corporate lobbyists and consultants, suggests the president-elect is backpedaling on his promise before he even enters the White House.

“It doesn’t look like they’re draining the swamp, it looks like they’re pouring the swamp into the transition,” Whitehouse said. “And if nothing changes, they’ll be pouring the swamp into the Oval Office as well.”

Members of Trump’s environmental transition team, for instance, include Myron Ebell to lead the Environmental Protection Agency transition, Michael McKenna in the Department of Energy, and Michael Catanzaro as an energy adviser. All have connections to the Koch brothers.

“It looks a little bit like if Donald Trump doesn’t watch his back, the Koch brothers are going to be running his administration for him,” Whitehouse told reporters.

During the campaign season, many of Trump’s supporters championed him as a political outsider, and Trump himself capitalized on that sentiment during rallies and speeches.

“We are going to send the special interests packing, and we are going to once again have a government of, by, and for the people,” Trump told a crowd in Des Moines, Iowa, in August.

Sanders said Trump’s actions in the days since the election don’t match the campaign promises.

“What we are now beginning to see is what I feared,” said Sanders, who lost the Democratic presidential nomination to Hillary Clinton. “And that is a lot of what Mr. Trump was saying to get votes turns out to be not what he intends to do as the president of the United States.”

Sanders said he and Whitehouse will continue to remind Americans of Trump’s promises. “We are going to do everything possible to hold him accountable,” Sanders said.