(CNN) Republican Sen. Mike Lee on Thursday criticized House Minority Leader Nancy Pelosi for repeatedly calling President Trump's chief strategist, Steve Bannon, a "white supremacist."

"I think this is nonsense," said Lee, speaking on CNN's "Wolf." "I think this is defamatory. I think she's acting with reckless disregard for the truth. I wish people would stop throwing out arguments like that."

Lee, the junior senator from Utah, was responding to Pelosi, who earlier in the day said she was stunned by the appointment of Bannon to the National Security Council and twice called him a white supremacist.

"It's a stunning thing, that a white supremacist would be a permanent member of the National Security Council," said Pelosi, D-California, speaking in her weekly news conference.

Lee said he does not object to the minority leader taking issue with President Trump's policies, but admonished her to avoid ad hominem attacks.

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