Haley responds to Trump questioning her husband's whereabouts amid deployment

At a campaign rally in Conway, South Carolina, on Saturday, former President Donald Trump hurled a new personal attack at Nikki Haley.

Mockingly, he questioned where her husband -- Maj. Michael Haley -- was, seemingly implying that there is something awry with their marriage and that is the reason he has not been with her on the campaign trail.

"Where's her husband? Oh, he's away. He's away," Trump mocked. "What happened to her husband? What happened to her husband? Where is he? He's gone. He knew. He knew."

Over 150 miles away at a campaign event in Gilbert, South Carolina, Nikki Haley responded to Trump's comments about the whereabouts of her husband, who is currently serving an active-duty deployment in the Horn of Africa for the South Carolina Army National Guard.

"I need to start with the fact that Donald Trump had a rally today and in that rally, he mocked my husband's military service," she began.

Nikki Haley minced no words in her rebuke, inviting the former president to say it to her face in a debate -- a request she has now continuously made on the campaign trail.

"And I'll say this, Donald, if you have something to say, don't say it behind my back," she asserted. "Get on a debate stage and say it to my face."

She then said that anyone who mocks the service of a combat veteran should not be president and again challenged Trump to take a mental competency test to prove his fitness to be president. He has dismissed the suggestion he has any issues.

"I have long talked about the fact that we need to have mental competency tests for anyone over the age of 75. Donald Trump claims that he would pass that -- maybe he would, maybe he wouldn't," Nikki Haley said. "But if you mock the service of a combat veteran, you don't deserve a driver's license, let alone being president of the United States."

Michael Haley also responded to the insult made by the former president. In a post on X, formerly Twitter, he tagged the former president as well as multiple news outlets and shared a meme. Bold white text overlaid a portrait of a wolf and read: "The difference between humans and animals? Animals would never allow the dumbest ones to lead the pack."

In an interview with CBS in 2015, Trump said the late Sen. John McCain -- who served in the Navy in Vietnam and was a prisoner of war for several years -- was "not a war hero." He told the interviewer: "I like people who weren't captured, OK?"

Trump has also been accused by former senior staff members of making disparaging comments about service members and veterans in private. A former chief of staff, John Kelly, attested to reports that he privately called deceased veterans "losers" and "suckers."

Trump has vigorously denied that and said, "I would be willing to swear on anything that I never said that about our fallen heroes. There's nobody that respects them more."

President Joe Biden tweeted Sunday morning in defense of Michael Haley's service while attacking Trump.

"The answer is that Major Haley is abroad, serving his country right now," Biden wrote in a post on X. "We know he thinks our troops are 'suckers,' but this guy wouldn’t know service to his country if it slapped him in the face."

ABC News' Libby Cathey contributed to this report.