Three rockets hit the Iraqi military air base of Balad north of Baghdad on Saturday, injuring one Iraqi contractor, Iraqi security officials said on Saturday.
No group immediately claimed the attack, reported Reuters.
It was the second salvo of rockets to hit a base hosting US forces or contractors in less than a week.
The officials spoke on condition of anonymity because they are not authorized to speak to the media.
Armed groups that some Iraqi officials say are backed by Iran have claimed similar incidents in the past.