The Veterans of Foreign Wars is demanding that President Donald Trump apologize for downplaying traumatic brain injuries sustained by US service members in Iraq after Iranian missile strikes on American troops earlier this month.

Earlier this week, Trump said he does not consider potential traumatic brain injuries to be as serious as physical combat wounds, minimizing the severity of the injuries, saying he heard that some troops "had headaches, and a couple of other things, but I would say, and I can report, it's not very serious."

"The VFW expects an apology from the President to our service men and women for his misguided remarks," William "Doc" Schmitz, VFW National Commander, said in a statement Friday, following the Pentagon's announcement that 34 US service members have been diagnosed with traumatic brain injuries in the January 8 Iranian attack.

"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," Schmitz added.

The VFW, described on its website as America's largest and oldest combat veterans service organization, said TBI is a "serious injury and one that cannot be taken lightly."

On Friday, the Pentagon announced that 34 US service members have been diagnosed with traumatic brain injuries in the January 8 attack, which was in retaliation for the January 2 US drone strike that killed a top Iranian general.

Of the 34 service members, 17 of those who were injured have since returned to duty in Iraq.

Nine service members are still being treated in Germany. An additional eight service members who had been flown to Germany have since been sent to the United States for additional treatment.

Although traumatic brain injuries are not always immediately apparent, the disclosure of injured US service members suggested that the attack's impact was more serious than initial assessments indicated.

Mild traumatic brain injuries, commonly known as concussions, are a form of TBI. The most common form of TBIs in the military are mild TBIs, according to the Defense and Veterans Brain Injury Center.