The Pentagon has not yet confirmed the strikes that reportedly killed eight civilians and a Syrian army officer.

Syrian state media say eight civilians have been killed by a U.S. airstrike in southwestern Syria, while other media reports also indicate that a strike has killed a Syrian army officer.

A Syrian army officer was killed in a U.S. strike on a Syrian army outpost near a U.S.-base close to the Iraqi-Syrian border, a commander in the Syrian government-alliance told Reuters.

Syrian media outlet SANA reported that a U.S.-led coalition strike bombed the town of Shafaa, killing at least eight civilians.

"Civil sources reported that at least eight citizens were killed, many others were injured and huge destruction affected the houses after warplanes of the US-led international coalition carried out many raids on the citizens' houses," SANA reported.

"The sources added that the aggression caused big destruction to the houses and infrastructure to a degree that forced the citizens to leave their houses, fleeing the fierce shelling of the coalition."

The Pentagon has not yet confirmed the strikes, saying only that on Thursday some U.S.-backed rebel groups engaged with an "unidentified hostile force" in the region, with no casualties.

Earlier this week, Syrian authorities said U.S.-coalition bombers had struck Syrian army positions near the Iraqi border between Albu Kamal and Tanf, but the U.S. military denied responsibility.

The rise in U.S.-coalition strikes coincides with the U.S. State Department saying it is "deeply troubled" by "increasing Syrian regime operations" in the region. The government had begun to retake territory in the region from U.S.-backed rebel forces.