Republican Rep. Ryan CostelloRyan Anthony CostellloGOP lawmaker rips Trump for Stormy Daniels attack: This is 'unbecoming of any man' Trump goes on 12-tweet Twitter tirade Trump calls Stormy Daniels 'Horseface' MORE (R-Pa.) on Friday called on the White House to fire special assistant Kelly Sadler over her derisive remarks about Sen. John McCainJohn Sidney McCainComey donates maximum amount to Democratic challenger in Virginia House race Live coverage: McSally clashes with Sinema in Arizona Senate debate Is there difference between good and bad online election targeting? MORE (R-Ariz.). 

"I think the White House should apologize and fire her. I think the remarks are disgusting. It's depressing, Craig, when you hear that kind of talk when you look at the service of Sen. McCain," Costello told CBS News host Craig Melvin.

"As a party, I think we need to do a better job of getting out in front of this stuff quickly, condemning it, and saying it has no place in our discourse," Costello added.

Echoing similar comments from former Vice President Joe BidenJoseph (Joe) Robinette BidenElection Countdown: Dems outraise GOP in final stretch | 2018 midterms already most expensive in history | What to watch in second Cruz-O'Rourke debate | Trump raises 0M for reelection | Why Dems fear Avenatti's approach The Hill's Morning Report — Presented by the Coalition for Affordable Prescription Drugs — Pollsters: White college-educated women to decide if Dems capture House Election Countdown: Cruz, O'Rourke fight at pivotal point | Ryan hitting the trail for vulnerable Republicans | Poll shows Biden leading Dem 2020 field | Arizona Senate debate tonight MORE, Costello said mocking a dying senator represented a degradation in America's political discourse.

During a closed-door meeting on Thursday, The Hill reported, Sadler dismissed McCain's opposition to President TrumpDonald John TrumpFive takeaways from Cruz, O'Rourke's debate showdown Arpaio files libel suit against New York Times IMF's Christine Lagarde delays trip to Middle East MORE's CIA director pick, Gina Haspel, stating “It doesn’t matter, he’s dying anyway.”

Sources familiar with the matter told The Hill that they believed the comment was meant as a joke, though it did not go over well with White House communications staffers present at the meeting.

McCain, 81, was diagnosed last year with an aggressive form of brain cancer, which he is receiving treatment for at his home in Arizona.

The White House is facing mounting scrutiny over its refusal to acknowledge the incident, drawing criticism from lawmakers on both sides of the aisle and members of the media.

ADVERTISEMENT

During Friday's daily press briefing, White House press secretary Sarah Huckabee Sanders refused to address the matter, dodging questions about Sadler's comments. 

“I'm not going to validate a leak, one way or another, out of an internal staff meeting," Sanders said at the briefing. 

Sadler, reportedly, has since apologized to the senator's daughter, Meghan McCain, who has also called for Sadler to be fired.

Meghan McCain, who co-hosts "The View," said Friday she couldn't understand an environment in which an aide could make such a comment and then "could come to work the next day and still have a job."