Democratic presidential candidate and former South Bend Mayor Pete Buttigieg ribbed President Donald Trump over his Vietnam War-era bone spur diagnosis.

"If you know anything about what has happened to troops in the post-9/11 wars ... it can be a lot more serious than bone spurs," said Buttigieg, a retired US Navy Reserve officer.

Buttigieg's comments came after Trump dismissed the seriousness of the traumatic brain injuries sustained by US troops in Iraq, likening them to "headaches."

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Democratic presidential candidate and former South Bend Mayor Pete Buttigieg ribbed President Donald Trump and his Vietnam-era bone spur diagnosis after Trump downplayed the significance of traumatic brain injuries that dozens of US service members were diagnosed with after Iranian missile strikes on Iraqi bases last month.

"You've got a president who will thump his chest, throw himself a military parade, and then turns his back on the troops," Buttigieg said on HBO's "Real Time with Bill Maher" on Friday, referring to the "Salute to America" parade on July 4, 2019.

"If you know anything about what has happened to troops in the post-9/11 wars ... it can be a lot more serious than bone spurs," added Buttigieg, a retired US Navy Reserve officer.

Trump was not required to serve in the Vietnam War after receiving five deferments: four for attending college and one for a bone spur diagnosis. Deferments were not uncommon during the Vietnam War, but Trump's absence — despite him being of military age throughout the war and his frequent boasts about his athleticism as a young man — raised questions among skeptics, including former Defense Secretary James Mattis.

"I earned my spurs on the battlefield ... Donald Trump earned his spurs from the doctor," Mattis joked during the 74th annual Al Smith dinner in New York on October 17.

'I heard that they had headaches'

US soldiers at a spot hit by Iranian missiles, at Ain al-Asad air base, in Anbar, Iraq. AP Photo/Qassim Abdul-Zahra

In early January, the Islamic Revolutionary Guard Corps, a wing of Iran's military, fired more than 20 missiles at two Iraqi military bases housing US troops in retaliation for a US drone strike that killed Iranian military leader Gen. Qassem Soleimani.

Sixty-four US service members were diagnosed with mild traumatic brain injury following the missile barrage. About 60% of those troops have returned to duty, Defense Department spokesperson Jonathan Hoffman said at a press briefing on Monday.

But Trump has dismissed the seriousness of TBI.

"I heard that they had headaches, and a couple of other things," Trump said during a press conference in Davos, Switzerland, in late January. "But I would say, and I can report, it's not very serious, not very serious."

The US Center for Disease Control and Prevention defines TBI as "a disruption in the normal function of the brain that can be caused by a bump, blow, or jolt to the head, or penetrating head injury."

The CDC adds that the severity of each TBI case can range from mild, "a brief change in mental status or consciousness," to severe, "an extended period of unconsciousness or amnesia after the injury."

Trump's remarks drew criticism from veterans groups, including the Veterans of Foreign Wars, one of the largest veterans organizations in the country.

"The Veterans of Foreign Wars cannot stand idle on this matter," VFW National Commander William Schmitz told Task & Purpose. "The VFW expects an apology from the president to our service men and women for his misguided remarks."

Months of campaigning by Democratic candidates are culminating to the Iowa Caucus, scheduled for Monday evening. Buttigieg is one of two Democratic candidates with previous military experience. Rep. Tulsi Gabbard of Hawaii is an officer in that state's Army National Guard.