The US military on Tuesday confirmed a helicopter "mishap" in northeastern Syria over the weekend that injured 22 US soldiers.
"The service members are receiving treatment for their injuries and 10 have been evacuated to higher care facilities," US Central Command said.
Central Command, which is responsible for overseeing US forces in the Middle East, said the cause of the crash was under investigation, "although no enemy fire was reported."
Approximately 900 US personnel and an undisclosed number of contractors have been deployed to Syria.
They are primarily based in the east as part of the ongoing mission to fight the remnants of the Islamic State.
While the influence of the Islamic State has waned dramatically since the caliphate was declared in 2014, pockets of fighters remain in remote areas outside the full control of the US-led coalition, the Syrian army, and their allies, including Russia and Iranian-backed militias.
The incident in Syria follows several incidents involving US military helicopters over the past few months.
In April, the US military temporarily grounded its pilots after three soldiers were killed after two helicopters collided and crashed during a training mission in Alaska.
In the previous month on Earth, 12 soldiers had died in four helicopter crashes.
Declaring the safety of its aviators a "top priority," the US Army has recommended special training for all active units.