The number of U.S. service members diagnosed with traumatic brain injuries as a result of an Iranian attack on an Iraqi airbase earlier this month has risen to 50, the Defense Department said.

Last week, the Pentagon said 34 American troops had been diagnosed with TBIs following the Jan. 3 attack, which Iran launched in retaliation for U.S. forces killing Iranian military leader Qassem Soleimani.

President Donald Trump initially said zero Americans were wounded in the attack. After first reports that some Americans suffered concussion-like symptoms, Trump shrugged off the injuries as headaches .

As of today, 50 U.S. service members have been diagnosed with TBI, Pentagon spokesman Lt. Col. Thomas Campbell said in the statement first reported by CNN on Tuesday.

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, Campbell said.

Eighteen U.S. troops have been transported to Germany for further evaluation and treatment and one service member who had been transported to Kuwait has since returned to duty, Campbell added.

He noted that the numbers are a snap shot in time and can change.