The base is located in Tel Baidar in the eastern Syrian province of Hasaka, Beirut-based Al Mayadeen reported.
The United States has set up 24 military bases and four outposts in Syria despite protests from the Syrian government.
US military installations in Syria and Iraq have been attacked on more than a single occasion following the escalation of the Israeli-Palestinian conflict last month.
While the United States blamed these attacks on groups affiliated with Iran, Tehran rejected these accusations.