President Donald Trump doubled down on his assertion on Monday that the injuries suffered by U.S. troops during an Iranian ballistic missile attack on U.S. forces are “not very serious” amid continued criticism.

Iran, swiftly retaliating over the death of Maj. Gen. Qasem Soleimani at the hands of the U.S. military, fired over a dozen ballistic missiles at US and coalition forces in Iraq in early January. In the immediate aftermath, the president announced that “no Americans were harmed” and moved to de-escalate tensions.

Since then, the number of U.S. troops who have been diagnosed with mild traumatic brain injuries has steadily risen from 109, the Pentagon revealed Monday in its latest update. The specific severity of which remains unknown,

Symptoms of a TBI can be slow to manifest and sometimes harder to detect than other injuries. The Department of Defense has offered this as an explanation for initial misreporting on injuries.

While roughly 70 percent of the injured have already returned to duty, 21 service members have been transported to the U.S. for additional care, suggesting their injuries may be more severe than those suffered by others.

In an interview with Fox Business Monday, the president commented on the situation.

“I don't think were looking to do too much damage, because they knew what the consequences were going to be,” Trump told Fox Business' Trish Regan. “I saw the missiles. We saw them going…. They landed in a way that they didn't hit anybody.”

The president said that he “stopped something that would have been very devastating for” the Iranians.

“And then a couple of weeks later I started hearing about people having to do with trauma,” he said. “Head trauma,” Trump continued, “That exists. But, you know, I viewed it a little bit differently than most, and I won't be changing my mind on that.”

Toward the end of January, when the number of troops who had been diagnosed with mild TBIs, concussions caused by the rattling of the brain, Trump told reporters that the injuries were “not very serious.”

“I heard that they had headaches and a couple of other things, but I would say and I can report that it's not very serious,” he told reporters in Davos, Switzerland. “I don't consider them very serious injuries relative to other injuries that I've seen.”

While it remains unclear exactly how severe the injuries are, veterans groups and traumatic brain injury awareness advocates have sharply criticized the president's comments.

The Veterans of Foreign Wars said in a statement that it “expects an apology from the president to our service men and women for his misguided remarks.”

“And, we ask that he and the White House join with us in our efforts to educate Americans of the dangers TBI has on these heroes as they protect our great nation in these trying times. Our warriors require our full support more than ever in this challenging environment.”

Read more from Business Insider: