Six rockets were fired on Monday evening towards Iraq's Balad airbase north of Baghdad, slightly wounding a foreign contractor working for a US company, an Iraqi security official said.
Three rockets fell in an area where US company Sallyport, which maintains F-16 aircraft bought by Iraq from the US, is based, the security source told AFP.
A foreign employee of Sallyport was slightly wounded, the source said.
Three other rockets were fired about 15 minutes later, reportedly falling near the base without hitting it.
Pentagon spokeswoman Cdr Jessica McNulty said no US or coalition troops were assigned at Balad, but US citizen contractors worked there.
Cdr McNulty said initial reports claimed there were no US casualties or damage.
It is the second attack against US interests in less than 24 hours, after two rockets were fired on Sunday at an airbase at Baghdad airport housing US-led coalition troops. There were no casualties.
There was no immediate claim of responsibility for either attack.
Sabreen, an online news service close to Iran-backed Iraqi militias, posted a picture on the Telegram messaging app showing at least seven rocket launchers lined on the ground ready to fire.
On the rockets were glued pictures of the slain commander of Iran’s Islamic Revolutionary Guards Corps’ Quds Forces, Gen Qassem Suleimani, along with the senior Iraqi militia leader, Abu Mahdi Al Muhandis.
It is one of many well-circulated pictures dating back to the fight against ISIS from front-lines. It shows Suleimani standing behind Al Muhandis while putting his left hand on Al Muhandis's shoulder, with both the Iraqi and Iranian flags flapping behind them.
The two influential leaders were killed in January 2020 in a US drone attack at the road of Baghdad International Airport along with several aides. Since then, Iran-allied militias have unleashed almost daily attacks on US assets in the country, demanding their withdrawal.
About 30 rocket or bomb attacks have been launched against US interests in Iraq, including troops, the embassy and Iraqi supply convoys to foreign forces, since President Joe Biden took office in January.
Two foreign contractors, an Iraqi contractor and eight Iraqi civilians have been killed in the attacks.
Washington routinely blames Iran-linked Iraqi factions for attacks on its troops and diplomats.
In early April, two rockets landed near Balad without causing casualties or property damage.
Also last month, an explosives-packed drone slammed into Iraq's Erbil airport. Officials said it was the first use of a drone against a base used by coalition troops in the country.
Dozens of other attacks were carried out in Iraq from autumn 2019 during the administration of Mr Biden's predecessor Donald Trump.
The operations are sometimes claimed by obscure groups that experts say are smokescreens for Iran-backed organisations long present in Iraq.
The strikes come at a sensitive time as Tehran is in talks with world powers aimed at bringing the US back into a 2015 nuclear deal.
The agreement, which curbs Iran's nuclear programme in exchange for sanctions relief, has been shaky since Mr Trump withdrew in 2018.
Pro-Iran Iraqi groups have vowed to increase attacks to force out the "occupying" US forces in recent months, sometimes against Tehran's wishes, some experts say.
