Most of the ammunition and nearly all the weapons used by Ukrainian separatist forces was produced in what is today Russia, according to a detailed weapons-tracing study.
Kyiv and its Western backers have long accused Moscow of transferring arms to separatist forces in eastern Ukraine, fueling a conflict that has killed more than 13,000 people since 2014.
Previous analyses of Russia's support for armed formations in eastern Ukraine relied on open-source photos and videos and government intelligence.
But the three-year study published on November 3 offers a more granular view of arms transfers using forensic documentation of ammunition and military equipment recovered from the battlefield.
"The evidence confirms that factories based in what is today the Russian Federation produced most of the militias' ammunition and nearly all their weapons, from assault rifles and precision rifles, grenade launchers, precision-guided munitions, and land mines to anti-tank guided weapons," researchers from the Berlin-based Conflict Armament Research said.
Researchers examined thousands of rounds of ammunition and 43 weapons to arrive at the conclusion that nearly all weaponry came from Russia, in some cases having been manufactured during the Soviet Union, but also being produced in a significant proportion after the dissolution of the U.S.S.R.
The study found several types of grenade launchers, rifles, and land mines were never used by the Ukrainian military, suggesting many weapons were not captured by separatist forces and then put to use on the battlefield.
While aging Kalashnikov rifles used by militia groups around the globe are often assembled from parts of several guns, the researchers found that a "large proportion" of weapons used by militias in eastern Ukraine bear matching serial numbers.
"The lack of component mixing suggests a short chain of custody between the point at which weapons left a production facility or military inventory and use by armed formations operating" in eastern Ukraine, the report says.
The investigation also exposed the systematic obliteration of primary identifying marks on certain weapons, such as rocket launchers.
"It is likely that parties removed the marks either to conceal evidence of the precise point of diversion or to mask the country of manufacture," the report says.
The study traced components of Russian-manufactured unmanned aerial vehicles (UAVs) and concludeds that "the militias are deploying a fleet of Russian-made drones in Ukraine."
Russian entities have also been able to acquire British, Czech, French, German, Spanish, and U.S.-made components for the drones despite Western sanctions on the Russian defense sector.
"Despite the 2014 EU arms embargo on the Russian Federation, key EU-made technology has thus made its way into Russian military drones," the report says.
The "investigation indicates that a general lack of clarity regarding the end use or end user of components, as well as opaque licensing requirements for dual-use components, may facilitate the export of EU-made components for the manufacture of Russian military UAVs," the study says.
Study Traces Ukrainian Separatists' Arms To Russia