Washington(CNN) Fifty US military personnel have now been diagnosed with concussions and traumatic brain injuries following the Iranian missile attack on US forces in Iraq earlier this month, according to a statement Tuesday from the Pentagon.

That's an increase of 16 from late last week when the Pentagon said 34 cases had been diagnosed.

"As of today, 50 U.S. service members have been diagnosed with TBI," Pentagon spokesman Lt. Col. Thomas Campbell said in the statement.

"Of these 50, 31 total service members were treated in Iraq and returned to duty, including 15 of the additional service members who have been diagnosed since the previous report. 18 service members have been transported to Germany for further evaluation and treatment. This is an increase of one service member from the previous report. As previously reported, one service member had been transported to Kuwait and has since returned to duty," the statement added.

Several Pentagon officials told CNN that the number of diagnosed cases is likely to continue to change. Approximately 200 people who were in the blast zone at the time of the attack have been screened for symptoms.

Although traumatic brain injuries are not always apparent immediately after they've been suffered, the disclosure of injured US service members indicates that the impact of the attack was more serious than initial assessments indicated. Tuesday's announcement is the third time the Pentagon has updated the figures for the numbers injured.

The Pentagon and President Donald Trump had initially said no service members were injured or killed in the January 8 Iranian missile attack, which was retaliation for the January 2 US drone strike that killed a top Iranian general.

Last week Trump said he does not consider potential brain injuries to be as serious as physical combat wounds, downplaying the severity of the injuries suffered in Iraq.

During the World Economic Forum in Davos, Switzerland, Trump was asked to explain the discrepancy between his previous comments that no US service member was harmed in the January 8 Iranian missile attack on Al-Asad airbase in Iraq, and the latest reports of US troops being treated for injuries sustained in that attack.

"No, I heard that they had headaches, and a couple of other things, but I would say, and I can report, it's not very serious," Trump replied during a news conference.

An influential veterans group demanded Trump apologize for those comments.

"The VFW expects an apology from the President to our service men and women for his misguided remarks," William "Doc" Schmitz, Veterans of Foreign Wars national commander, said in a statement Friday.

"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 most common form of TBIs in the military are mild TBIs, according to the Defense and Veterans Brain Injury Center.