Five rockets were fired at Iraq's Balad airbase on Wednesday evening, with two of them falling near an area used by US contractors but without causing casualties, a security official said.
"There were no victims or damage," the official said.
Balad airbase, north of Baghdad, is used by US company Sallyport to service F-16 fighter jets flown by Iraq's air force and has repeatedly been the target of rocket fire.
Another US company, Lockheed Martin, withdrew its staff from the base last month amid concerns about their safety.
At least three foreign subcontractors and one Iraqi subcontractor have been wounded in attacks on Balad.
The US routinely blames the attacks and those on other bases, including Baghdad airport, on Iran-backed militias.
US troops are in Iraq as part of a military coalition that was established to fight ISIS in a campaign that Iraq's government declared was won in late 2017.
The rocket attacks are regarded as a way to pressure Washington into removing all of its remaining personnel, who Iran-linked factions view as an occupying force.
In mid-April, pro-Iran fighters sent an explosives-packed drone crashing into Erbil airport in the first reported use of such a weapon against a base housing US troops in Iraq.