A civilian U.S. defense contractor has been killed in a rocket attack on an Iraqi military base near the oil-rich city of Kirkuk, the Pentagon says.
U.S. officials said several U.S. and Iraqi troops were also injured in the December 27 attack.
Officials said as many as 30 rockets were fired at the K1 military base, which is an Iraqi compound where U.S. personnel are also stationed.
Security sources told Reuters that personnel found a launch site for Katyusha rockets inside an abandoned vehicle close to the base.
No group claimed responsibility for the attack.
Islamic State (IS) extremists operate in the area, but a senior U.S. military official said this month that attacks by Iranian-backed groups on bases housing U.S. forces were increasing and becoming more sophisticated.
In December, U.S. Secretary of State Mike Pompeo blamed Iranian-backed forces for a series of attacks on bases in Iraq and warned Iran that any attacks by Tehran or proxies that harmed Americans or allies would be “answered with a decisive U.S. response.”
Tensions have increased between Tehran and Washington since last year when U.S. President Donald Trump pulled the United States out of the 2015 nuclear deal and reimposed crippling sanctions.
Iraq has been shaken since the beginning of October by anti-government and anti-Iranian protests that have led to the deaths of more than 450 people amid a violent crackdown by authorities.