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 drone was thought to be armed and threatening US-led coalition troops on the ground, officials said.
It was shot down near Tanf, an outpost of the US-led coalition.
This is the latest incident in the skies over Syria, after the US shot down a Syrian fighter plane on Sunday and another drone earlier this month.
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 incident underscores the growing tensions in the region as a battle develops for the control of eastern Syria, BBC defence and diplomatic correspondent Jonathan Marcus says.