The US military said on Sunday that a report claiming four of its members were killed in north-eastern Syria is false.
The Syrian national news agency Sana reported earlier on Sunday that a roadside bomb blew up a US military vehicle on a road outside the town of Markada, between Hasakah and Deir Ezzor.
A spokesman for Operation Inherent Resolve, the US-led coalition fighting ISIS, Col Wayne Marotto, tweeted that all of its troops were accounted for and that the claims were false.
The US has about 500 troops in north-east Syria and works closely with the Syrian Democratic Forces, a group of opposition militias led by Kurdish units.
In September, the US Army sent more troops and equipment to north-east Syria.