“There were no casualties or damages,” the official said.
The Balad air base, north of Baghdad, is used by the US company Sallyport to service F-16 fighter jets flown by the Iraqi air force and has been repeatedly targeted by rockets.
Another US company, Lockheed Martin, withdrew its personnel from the base last month amid concerns about the safety of its personnel.
At least three foreign subcontractors and one Iraqi subcontractor have been injured in attacks on Balad.
The United States routinely blames such attacks, which also often target US interests in other facilities, including the Baghdad airport, on Iranian-backed factions.
US troops are in Iraq as part of a military coalition that was established to fight the jihadist group Islamic State, a campaign that the Iraqi government declared won in late 2017.
The rocket attacks are seen as a means of pressuring Washington to withdraw all of its remaining personnel, whom Iran-linked factions view as an occupying force.
In mid-April, pro-Iran fighters sent an explosives-laden drone that crashed into Arbil airport in the first reported use of such a weapon against a base housing US troops in Iraq.