RNC Chairman Reince Priebus Called Donald Trump to Express Concerns About Campaign It's a sign of growing angst in the GOP over Trump's campaign.

 -- Republican National Committee Chairman Reince Priebus called Donald Trump Tuesday to express frustration with the presidential candidate’s campaign and how he has handled his feud with the family of a slain Muslim American soldier, according to several party sources familiar with the conversation.

It’s a sign of the growing angst in the GOP over a candidate who has veered away from his core talking points since the conclusion of last month’s Republican National Convention.

The parents of fallen Army Capt. Humayun Khan, who was killed in Iraq in 2004, were featured at last week’s Democratic National Convention. The father, Khizr Khan, criticized Trump’s anti-Muslim rhetoric and said the real estate mogul has “sacrificed nothing and no one” for the country.

Trump fired back, saying he was “viciously attacked” by the Khans. He questioned why Ghazala Khan, Humayun Khan’s mother, remained silent onstage, insinuating that she wasn’t allowed to speak because she is Muslim.

“If you look at his wife, she was standing there. She had nothing to say. She probably, maybe she wasn't allowed to have anything to say. You tell me, but plenty of people have written that she was extremely quiet, and it looked like she had nothing to say,” Trump said in a recent interview with ABC News’ George Stephanopoulos.

Trump, who secured the Republican presidential nomination during his party’s convention two weeks ago, remained defiant Tuesday. He told a Virginia television station that he doesn’t “regret anything” about his drawn-out discord with the Khan family. And in an interview with The Washington Post, Trump refused to endorse for re-election Republicans who have criticized him, including House Speaker Paul Ryan of Wisconsin and Sen. John McCain of Arizona.

“I’m just not quite there yet,” Trump said of backing Ryan.

Ryan told CNN’s Jake Tapper something similar in May, saying he couldn’t yet support Trump. “I’m just not ready to do that at this point. I’m not there right now,” Ryan said. He endorsed Trump in June.

Priebus, who has been friends with Ryan for years, voiced his concerns to Trump over the telephone, the Republican Party sources said.

Some staffers for Trump’s campaign have also expressed their frustration with the White House hopeful, according to sources familiar with the situation.

But senior-level Trump campaign sources say there is “no disunity” in their ranks and that they are “completed focused ... The election is about Hillary Clinton.”