North Korea has relied heavily on counterfeit U.S. and European parts to produce missiles and drones used in the war against Ukraine, a new report has found, suggesting that sanctions are limiting Pyongyang’s ability to source original components.

The U.K.-based Conflict Armament Research (CAR) project analyzed North Korean Hwasong-11-series missiles used by Russia against Ukraine and determined that “half of the 81 components … have been flagged as suspected or confirmed counterfeits,” according to its September report.

The presence of counterfeits “can function as an indicator of the effectiveness of international sanctions and trade controls,” the researchers said, despite