At least 100 militants were killed in the Coalition's attack, a USA military official told reporters on Wednesday.
The attack was a response to a pro-Assad airstrike on the headquarters of a long-time USA ally in Syria.
Still, some US troops had been embedded at the time with Syrian Democratic Forces (SDF), whose headquarters in Syria's Deir al-Zor province had been a target of the attack.
Some US forces are embedded with the SDF but they suffered no casualties. According to a report at Politico based on comments by coalition public affairs director Col. Thomas Veale, the battle began on Tuesday night and lasted into Wednesday morning.
The US maintains about 2,000 troops in Syria, who mostly work with the over 50,000-strong Syrian Democratic Forces, a mix of Kurdish and Arab fighters who have been the primary US-backed force fighting ISIS in Syria. Up to 30 artillery and tank rounds came within 500 yards of an SDF headquarters. The US also shot down a pro-regime drone after it dropped a munition in the vicinity of US troops in Syria.
A US Navy F/A-18 shot down a Syrian regime Su-22 jet in June that had attacked US-backed forces on the ground.
"In defense of Coalition and partner forces, the Coalition conducted strikes against attacking forces to repel the act of aggression against partners engaged in the Global Coalition's defeat-Daesh [ISIS] mission", read the statement. A USA military official who spoke on condition of anonymity had earlier said the US strikes killed around 100 troops, but Veale said the military does not have an exact figure for the casualties.
According to Liveuamap, a site that maps the conflict in Syria, the town of Khusham near Deir ez-Zor is actually held by the Syrian regime while the nearby Conoco-Tabiya gas plant is several kilometers from the line that separates the SDF from the regime. The attack had left "scores of persons dead and others injured" and caused "huge damage" to the area, SANA added.
Officials said it appeared that the pro-regime forces were trying to take back land that the SDF had liberated from Daesh last September, including oil fields in Khusham.
The main component of the SDF, known as the People's Protection Units (YPG), is the target of a military operation in northern Syria by Turkey, which considers the YPG a terrorist group.
Though some of the anti-Assad resistance has become entwined with Islamist groups like Al Qaeda, the USA vets the groups it works with, and maintains that the SDF are moderate rebels who were instrumental in the defeat of ISIS.