Lieutenant Colonel Thomas Campbell said on January 28 that 16 more service members were now diagnosed with brain injury, bringing the total to 50.
Thirty-one of the 50 were treated and had returned to duty, Campbell added.
In its previous update last week, the Pentagon said that 34 U.S. service members had suffered injuries.
Initially, President Donald Trump claimed that no Americans were harmed in Iran’s January 8 attack on the Ain al-Asad air base in western Iraq.
Concussions can cause headaches, dizziness, sensitivity to light, and nausea.
Trump has downplayed the injuries saying he “heard that they had headaches and a couple of other things.”
The remarks angered a U.S. war veterans group.
William Schmitz, national commander of the Veterans of Foreign Wars, said on Friday the group “expects an apology from the president to our service men and women for his misguided remarks.”
Iran’s attack was in retaliation for the U.S. killing of its top military commander, Major General Qasem Soleimani, in a drone strike at Baghdad airport on January 3.
There were some 1,500 U.S. soldiers at the Ain al-Asad base at the time of the attack. Most had been huddling in bunkers after being alerted about the incoming missiles.