Washington (CNN) White House aide Kelly Sadler responded to Sen. John McCain's opposition to President Donald Trump's pick for CIA director by saying Thursday morning that "he's dying anyway," a White House official told CNN.

The official said Sadler, who is in charge of surrogate communications, meant it as a joke, "but it fell flat."

McCain announced last year that he had been diagnosed with brain cancer, and he issued a statement Wednesday calling on his fellow senators to oppose Gina Haspel, Trump's nominee for CIA director, whose ties to the use of interrogation methods widely considered torture have drawn significant criticism.

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."

Sadler called the senator's daughter Meghan McCain on Thursday to apologize for the remark, a source close to the situation told CNN, although it's unclear what her response was.

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