Majority Leader Mitch McConnell asked President Donald Trump in one of their first meetings to stop his talk of "draining the swamp," according to former White House chief strategist Stephen Bannon.

In an interview to air Sunday on CBS News'"60 Minutes," Bannon decried the lack of support from the Republican establishment for the new president.

"I think Mitch McConnell, and to a degree, [House Speaker] Paul Ryan… do not want Donald Trump's populist, economic nationalist agenda to be implemented," he told host Charlie Rose. "It's very obvious… obvious as night follows day."

Asked to give an example of how they were "trying to nullify the 2016 election," Bannon recalled an early meeting at Trump Tower.

"Mitch McConnell when we first met him… I think in one of the first meetings in Trump Tower with the president, as we're wrapping up, he basically says, 'I don't wanna hear any more of this 'drain the swamp' talk,'" Bannon said.

"He… flat out. He goes, 'A guy up on Capitol Hill can't buy a Coke unless it's gotta be reported. I can't -- I can't hire any smart people' because everybody's all over him for reporting requirements and the pay, et cetera, and the scrutiny," Bannon continued.

"You know, 'You gotta back off that.' The 'drain the swamp thing' … Mitch McConnell was day one did not wanna -- did not wanna go there. Wanted us to back off."

Bannon was unapologetic about his critique of some leading GOP members, saying they "do not support the president's program. It's an open secret on Capitol Hill. Everybody in this city knows it," and said that was "absolutely" why he is going to war with them.