The attack caused a large fire at the refinery, briefly halting operations, the country’s oil ministry said.
The fire hit a fuel storage tank at the small Siniya refinery in Salahuddin province on Sunday. There were no reports of casualties, the ministry statement said.
The fire was extinguished and operations resumed within few hours after the attack, the ministry said, citing the state-owned Northern Refining Company that runs the refinery.
The Daesh terrorist group said on its website Amaq that two Katyusha rockets were used in the attack, Al Jazeera reported.
The Siniya refinery is near Iraq’s largest oil refinery, Baiji, which sustained considerable damage during the war against Daesh. The refinery was overhauled and eventually reopened in 2017 following the group’s defeat.
Although Daesh no longer holds territory in Iraq, the group maintains sleeper cells and frequently carries out attacks across parts of the country, including the north.