A White House communications official mocked Sen. John McCain's brain cancer diagnosis in a meeting after the Arizona Republican announced his opposition to President Trump's pick to lead the CIA, sources told Fox News Thursday.

According to two White House sources, the staffer, Kelly Sadler, said of McCain, "It doesn't matter, he's dying anyway."

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White House sources said the joke at first elicited some nervous snickers. Afterward, though, the sources said many spoke to each other about being surprised by the "tasteless" remark.

Sadler's comments were first reported by The Hill, which said she made them during a closed-door meeting of about two dozen White House communications staffers on Thursday morning.

Late Wednesday, McCain urged his Senate colleagues to oppose Gina Haspel's nomination as CIA director over her role in the "enhanced interrogation program" enacted by the George W. Bush administration after the Sept. 11, 2001, terrorist attacks.

"I believe Gina Haspel is a patriot who loves our country and has devoted her professional life to its service and defense," McCain said in a statement. "However, Ms. Haspel's role in overseeing the use of torture by Americans is disturbing. Her refusal to acknowledge torture’s immorality is disqualifying."

There was no immediate response from Sadler, the White House or McCain's office.

Following the comment, McCain's wife, Cindy, tweeted a direct comment at Sadler.

"May I remind you my husband has a family, 7 children and 5 grandchildren," the tweet said.

According to her LinkedIn profile, Sadler has worked for the White House communications office since May of last year. Before her hiring, she was a reporter and editor for The Washington Times newspaper.

Fox News' Chad Pergram contributed to this report.