A number of Katyusha rockets on Monday night targeted Iraq's Taji base where the US-led Coalition forces are based, reports said.
Initial reports noted that at least three rockets hit the base in north of the capital Baghdad. However, other sources later said that the number of rockets was four.
US helicopters were seen flying over the camp after the four 107mm rockets were fired at the base.
Pro-Iranian Usbat El Thaereen has claimed responsibility for the attack.
Sources were cited as claiming that there were casualties while the Iraqi army and coalition forces are yet to comment on the incident.