Twenty-two U.S. service members were injured in a helicopter “mishap” in northeastern Syria on Sunday, the U.S. military said late on Monday, without disclosing the cause of the incident or detailing the severity of the injuries.
U.S. Central Command said 10 service members were evacuated to higher-level care facilities outside the region.
Central Command, which oversees U.S. troops in the Middle East, said no enemy fire had been reported but added that the cause of the incident was under investigation.
Officials at U.S. Central Command did not immediately respond to requests for further information.
The incident took place near the town of Shaddadi in the province of Hasakeh, according to two security sources.
The U.S.-backed Syrian Democratic Forces (SDF), which control swathes of northeast Syria, referred questions to the U.S.-led coalition under which American troops are deployed in the zone.
General Mazloum Abdi, commander in chief of the SDF, said in a statement: “We wish a speedy recovery for the wounded of the crashed US helicopter in northeast Syria. We assure our commitment to continue working with our partners from the coalition against ISIS to ensure the stability of the region.”
The autonomous Kurdish-led administration that governs the area and the central Syrian government in Damascus did not immediately respond to requests for comment.
About 900 U.S. personnel are deployed in Syria, most of them in the east, as part of a mission fighting the remnants of Islamic State. They have come under repeated attacks in recent years by Iran-backed fighters.
In March, 25 U.S. troops were wounded in strikes and counter-strikes in Syria, which also killed one U.S. contractor and injured another.
U.S. forces first deployed into Syria during the Obama administration’s campaign against Islamic State, partnering with a Kurdish-led group called the Syrian Democratic Forces.
While Islamic State is now a shadow of the group that ruled over a third of Syria and Iraq in a caliphate declared in 2014, hundreds of fighters are still camped in desolate areas where neither the U.S.-led coalition nor the Syrian army, which is supported by Russia and Iranian-backed militias, exert full control.
Thousands of other Islamic State fighters are in detention facilities guarded by the SDF.
U.S. officials say that Islamic State could still regenerate into a major threat.
The threats from Iran-backed militia to U.S. forces are a reminder of the complex geopolitics of Syria, where Syrian President Bashar al-Assad counts on support from Iran and Russia and sees American troops as occupiers.