More than 100 U.S. service members have been diagnosed with mild traumatic brain injuries after the January 8 Iranian missile attack on the al Asad military base in Iraq.

According to CNN, that's an increase of at least 36 cases from the end of January when the Pentagon said 64 service members had been diagnosed with injuries.

Last month, several Pentagon officials told CNN the number of diagnosed cases is likely to continue to change. 

About 200 people who were in the blast zone at the time of the attack have been screened for symptoms.  

During a news conference at the Pentagon late last month, Joint Chiefs Chairman Gen. Mark Milley said the increasing number of reported cases stems in part from the fact that the injuries, for the most part, fall into the category of "mild TBI" which takes time for symptoms to manifest.

"All of those people were screened and we have got a certain number and the number is growing, in this particular case TBI -- that manifests, it takes some time to manifest itself, it's not an immediate thing necessarily -- some cases it is, some cases it's not. So we continue to screen," Milley said.

"Some of them have been evacuated to Europe, some have been evacuated back to the United States so there is a layered approach to this, we'll continue to do that with our medical professionals."