Former California Gov. Arnold Schwarzenegger (R) urged Americans against "falling toward our lowest instincts" Saturday in response to a White House aide mocking Sen. John McCain John Sidney McCainCindy McCain endorses Biden: He's only candidate 'who stands up for our values' Biden says Cindy McCain will endorse him Biden's six best bets in 2016 Trump states MORE's (R-Ariz.) terminal cancer diagnosis.

The actor and former GOP politician tweeted Saturday that McCain "is a hero who has given his entire life in service to his country," adding that Americans should reach for their "better angels."

.@SenJohnMcCain deserves respect. We must stretch for our better angels instead of falling toward our lowest instincts. pic.twitter.com/BYbcVAbeg6 — Arnold (@Schwarzenegger) May 12, 2018

"I hope this horrible 'joke' from someone in the White House is a wake-up call to all Americans to think about how we speak to each other about our politics," he wrote in an attached statement.

"We can be strong without being cruel; tough without being mean spirited," Schwarzenegger said.

ADVERTISEMENT

Schwarzenegger joined a chorus of anger from both sides of the aisle this week after The Hill reported that White House aide Kelly Sadler quipped to communications staffers during a closed-door meeting that McCain's rejection of President Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE's CIA pick Gina Haspel "doesn’t matter, he’s dying anyway.”

The White House did not dispute or confirm the remarks in a statement to The Hill, or in a press briefing Friday with press secretary Sarah Huckabee Sanders.

“We respect Senator McCain’s service to our nation and he and his family are in our prayers during this difficult time,” the White House said in a statement to The Hill.

Sanders refused to address the issue at a Friday briefing amid numerous calls for Sadler to publicly apologize and to be fired, instead calling the issue a staff matter.

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