A drone attack has targeted a US military base near Syria's border with Iraq, US officials and a war monitor said.

Axar.az reports that in a statement to Anadolu Agency late on Wednesday, a US official confirmed the attack on the Al Tanf military base in Syria's southwestern Rif Dimashq governorate where US forces are deployed.

There were no casualties among American forces, the official said.

"We know of no casualties," an official said on condition of anonymity to the AFP news agency.

"Explosions resounded from the Al Tanf base used by the US-led coalition" fighting Daesh group, the Britain-based Syrian Observatory for Human Rights said.