Washington (CNN) A Democratic senator called on President Donald Trump Friday to repudiate a White House aide's comment about "dying" Republican Sen. John McCain, who has brain cancer.

"The President should be saying that 'This was unacceptable. Under my watch, I will not tolerate such comments.' But we haven't heard a word from the President," Sen. Ben Cardin from Maryland said in an interview on CNN's "New Day."

White House aide Kelly Sadler had responded to McCain's opposition to Gina Haspel's nomination for CIA director by attempting to joke Thursday morning that "he's dying anyway," a White House official told CNN. Asked about Sadler's comment, a White House official said, "We respect Senator McCain's service to our nation, and he and his family are in our prayers during this difficult time."

When asked if top Senate Republicans should speak out against the comments, Cardin said all leaders should.

"Leaders have a responsibility to speak out when things are done that are against the traditions and values of this country. And that statement went beyond what is acceptable," Cardin said.

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