Syrian media outlets reported that the missile attack targeted the base in Syria's al-Omar Oilfield in the eastern side of Deir ez-Zur on Saturday.
According to the reports, at least six missiles were fired towards the military base during the attack.
No individual or group has so far claimed responsibility for the missile attack.
The projectiles were fired from the direction of Deir ez-Zur's al-Hanawi and al-Mazare' areas, the reports added, noting that American warplanes and helicopter gunships were seen loitering over the site of the attack during its immediate aftermath.
Over the past months, the US base has come under several such attacks.
ZZ/