President Donald Trump on Wednesday downplayed the injuries suffered by U.S. soldiers during Iran’s attack on a military base in Iraq earlier this month, suggesting he doesn’t consider traumatic brain injuries to be “very serious.”

Trump has said several times that no Americans were hurt when Iran launched a missile attack against Ain al-Asad air base on Jan. 8 in retaliation for U.S. forces killing Iran military leader Qasem Soleimani. But the Pentagon acknowledged last week that 11 U.S. soldiers required medical attention outside of Iraq as a result. Eight suffered concussion-like symptoms and three sought behavior-health treatment.

CBS News reporter Weijia Jang asked Trump Wednesday about the injuries during a news conference at the World Economic Forum in Davos, Switzerland.

“Initially, you said repeatedly to Americans that after Iran retaliated for the Soleimani strike no Americans were injured,” Jang said. “We now know at least 11 U.S. servicemen were airlifted from Iraq. Can you explain the discrepancy?”

“No, I heard that they had headaches and a couple of other things,” Trump responded. “But I would say, and I can report, it is not very serious.”

The U.S. Centers for Disease Control and Prevention defines a concussion as a traumatic brain injury that can occur from a blow to the head. Concussions are not usually considered life-threatening, but their effects can be serious.

Asked Wednesday if he considers potential traumatic brain injuries to be “serious,” Trump suggested he did not and urged Jang to follow up with the Defense Department because he was only told about the injuries “numerous days later.”

“I don’t consider them very serious injuries relative to other injuries that I’ve seen,” the president said. “I’ve seen what Iran has done with their roadside bombs to our troops. I’ve seen people with no legs and no arms. ... I can consider them to be really bad injuries. No, I do not consider that to be bad injuries.”

Susan Connors, president and CEO of the Brain Injury Association of America, said in a statement that her group was “disappointed” by Trump’s remarks.

“A brain injury changes the way you move, act, think, and feel ― it has the potential to change who you are at your core,” Connors said. “What could be more serious than that?”

She added: “As the nation’s oldest and largest brain injury advocacy organization, BIAA is disappointed in the President’s characterization of TBI as ‘just a headache’ and especially in his implication that those who sustain TBIs in service for their country are not suffering serious injuries.”

Watch Trump’s full news conference below. His remarks about the soldiers’ injuries begin around the 53-minute mark.

This story has been updated with comments from the Brain Injury Association of America.