The number of confirmed injuries to US personnel at an Iraqi air base has risen for the fourth time since an attack by Iran on the site.
Pentagon officials have confirmed a new total of 64 cases of traumatic brain injury (TBI), following the Iranian strikes on Al Asad air base on 8 January.
This week, the number of cases has increased twice again - first to 50 and now 64.
Senior officials have defended the growing number of disclosed cases.
Joint Chiefs of Staff chairman, General Mark Milley, explained why original reports may have been so far from the current figure.
"When we're in a firefight... the very first thing you're focusing on is life and limb," he said.
"When we say 'reported casualties' - we're really talking about killed in action (KIA) and serious injuries like loss of limbs.
"TBI manifests itself over time - it's not necessarily instantaneous."
US Defense Secretary Mark Esper has stood by official numbers released by the US at any given time to date.
"At that time, as reported, there were no casualties - over time you learn things," he said, claiming the injury report was always likely to snowball.
A total of 15 missiles were fired at two bases during the 8 January attack in Iraq, with 10 targeting Al Asad, in retaliation for the US assassination of Iranian General Qassem Soleimani.
Despite Mr Trump releasing a statement on 8 January, stating "all is well", Gen Milley said he was unsurprised the blasts have had a follow-on impact on the health of US troops in Iraq.
"There's concussive injuries from as a result of any explosive device that goes off," he said.
Blows to the head and parachute jumping were also listed as potential risks, while Mr Esper warned that TBI can occur in training as well as the battlefield.
Therapy and screening processes are said to have been taken, alongside preventative measures such as helmet design, to prevent brain injuries among the troops.
Mr Esper believes America are world leaders in the development of such measures - but called for further research into the field.
Gen Milley said these "unseen wounds of war" can vary between individuals and can depend on proximity to blasts.
"Sometimes they are lifelong, sometimes they resolve themselves in weeks or months," he said.
The general says that brain damage can result in Post-traumatic stress disorder (PTSD), which affects veterans across the UK and worldwide.
The UK's Ministry of Defence now says none of its personnel were present at the site during the time of the attack, although British troops are thought to have been in Erbil.
Tension between the West and Iran have spiked in the aftermath of General Soleimani's death, including uncertainty over the 2015 nuclear deal - negotiated to prevent the Middle Eastern nation from obtaining a nuclear weapon.
Cover image: Al Asad Air Base defences being strengthened by US soldiers and contractors (Picture: US Army).