A US jet has shot down an Iranian-made drone operated by forces backing the Syrian government in the south of the country, American officials say.
The F-15 plane downed the drone around 00:30 on Tuesday (21:30 GMT Monday) north-east of Tanf, according to a US military statement.
The drone was thought to be armed and threatening US troops on the ground, officials said.
Tanf, near the borders with Iraq and Jordan, is home to a coalition base.
If confirmed, it is the second downing of a drone this month.
A Syrian jet was also shot down in northern Syria on Sunday evening.
Russia, which has an air contingent deployed in Syria in support of President Bashar al-Assad, warned after that attack that it would track coalition aircraft with missile systems and military aircraft, though it stopped short of openly saying it would shoot them down.
The Tanf base has been used by Western special forces.
Source: world bbc