More than 100 American service members have traumatic brain injuries from Iranian airstrikes on Al Asad Air Base in Iraq in January, the Defense Department said, a number that was more than 50 percent higher than previously disclosed.
Of the 109 troops who have been diagnosed with brain injuries, 76 had returned to duty, officials said Monday.
The latest tally, which has steadily grown since the Jan. 8 strike, drew a sharp contrast with the assertion by the Trump administration in the hours after the attack that no Americans were hurt. The number also underscored the unseen effects of traumatic brain injuries, which sometimes do not manifest symptoms for days or weeks but can have long-term physical or mental effects.
And as the injury toll has mounted, veterans groups and others have levied criticism at the White House, in part because, in January, President Trump dismissed the injuries as “not very serious.”
“I heard that they had headaches and a couple of other things,” Mr. Trump said at a news conference Jan. 22 in Davos, Switzerland. “I don’t consider them very serious injuries relative to other injuries I have seen.”
At least a dozen missiles were fired during the attack, which was a retaliation for the killing of a top Iranian general, Qassim Suleimani, by an American drone strike in Baghdad on Jan. 3. The Trump administration at first said there were no injuries, but a week later said several service members were evaluated for possible concussions.
Then, days after Mr. Trump’s statements in Davos, the Defense Department said that 34 people had suffered brain injuries. The number was later increased to 50 and then to 64, with military officials saying that the symptoms of traumatic brain injuries could take weeks to appear.
The repeated revisions have drawn outrage from some veterans and senators.
“The number just keeps going up,” Paul Rieckhoff, the founder of Iraq and Afghanistan Veterans of America, said on Twitter on Monday. “It’s time for Congress to demand a full investigation. The public and our military families deserve the truth.”
Frank Luntz, a longtime Republican strategist, said on Twitter on Monday that a traumatic brain injury “can have debilitating lifelong effects.”
“We shouldn’t hide our veterans’ injuries just to pretend like we’re invincible,” he said.
Traumatic brain injuries can result from the powerful changes in atmospheric pressure that accompany an explosion like that from a missile warhead. Only in the last several years has the Pentagon made a considerable effort to understand the injuries.
Mr. Trump’s statements appeared to echo sentiments common in the early years of the wars in Iraq and Afghanistan, where troops rattled by explosions were visibly uninjured and ushered back to duty, only to have long-term effects from the blasts manifest weeks and months later.
Defense Secretary Mark T. Esper said at a news conference in January that the Pentagon took those types of injuries “very seriously.”
The White House did not immediately respond to questions on Monday afternoon.