Five rockets landed on Tuesday on Ain al-Asad airbase, which hosts U.S. forces in Anbar province in western Iraq, an Iraqi military statement said.
No casualties were reported, it added, giving no further details.
The top U.S. general, Mark Milley, visited Iraq last Tuesday amid a spate of anti-government protests in the Middle East and questions about how they could impact Iranian influence in the region.
Some experts believe that protests in the region, including those in Iran itself, could give the United States an opportunity to reduce Tehran's regional influence. But they warn they could hurt American interests as well.
"Everybody looking at popular protests in the Middle East has to keep very much in mind that we rarely have an idea where these are going to go," said Jon Alterman, a Middle East expert at the Center for Strategic and International Studies.
"It could displace a number of vital partners as it could displace the Iranians... Ultimately, I don't think you can ever get the Iranians out of Iraq," Alterman said.
There are more than 5,000 U.S. troops in Iraq supporting local forces, though Iraq has rejected any long-term presence of additional U.S. forces that crossed its border during an American drawdown from northern Syria.