TOPSHOT-UKRAINE-RUSSIA-CONFLICT-WAR

A Ukrainian serviceman aims a Stinger air-defense system (MANPADS) during a joint military training in Rivne region, near the border with Belarus, on February 11, 2023, amid the Russian invasion of Ukraine. (Photo by DIMITAR DILKOFF/AFP via Getty Images)

WASHINGTON — The US has failed to properly track more than $1 billion-worth of high-tech weapons systems sent to Ukraine, though inventory processes are getting better, according to a new report from the Pentagon’s inspector general.

“While the DoD has improved execution of EEUM [enhanced end-use monitoring] since the full-scale invasion began in February 2022, the DoD did not comply with the EEUM program requirements for defense article accountability in a hostile environment,” says the partially redacted report, published Wednesday.

The report says that as of June 2023, though US European Command’s Office of Defense Cooperation-Ukraine and the Ukrainian military “conducted some required inventories, […] serial numbers for more than $1.005 billion of the total $1.699 billion (59 percent of the total value) of EEUM-designated defense articles remained delinquent.”

RELATED: High-tech trench warfare: 5 hard-won lessons-learned for the US from Ukraine

As the name implies, enhanced end-use monitoring articles refers to higher-end systems that require closer tracking than regular end-use monitoring articles. According to the IG, that includes a host of missiles and their launch systems — from Tomahawks to Stingers — as well as some unmanned aerial vehicles and even night vision goggles.

The IG said it “statistically sampled” 303 EEUM-designated systems between February 2022 and March 2023 and found that less than half had been properly inventoried by either American or Ukrainian personnel.

“This occurred because ODC-Ukraine’s personnel limitations negatively impacted their ability to conduct initial inventories at logistics hubs in a neighboring partner nation, and their limited EEUM personnel and movement restrictions within Ukraine constrained their ability to conduct required inventories inside Ukraine,” the report says.

RELATED: NATO signs off on $5.5B contract for hundreds of Patriot missiles

In all, the report says that as of February 2023, 87 percent of EEUM-designated articles were delinquent in tracking databases, though that figure improved to 60 percent by June 2023.

“Until those challenges are resolved, the DoD will not be able to fully account for all of the more than $1.699 billion in EEUM-designated defense articles provided to Ukraine,” the report says.

The $1.6 billion in EEUM aid examined by the IG is a fraction of the over $44.2 billion in security assistance [PDF] the US has provided Kyiv since Russia’s invasion, but the report comes as aid packages have become more politically fraught on Capitol Hill, especially in the mind of some vocal Republican lawmakers.

In February 2023, then-senior Pentagon official Colin Kahl testified before lawmakers that the US did not believe US weapons sent to Ukraine were being diverted, but acknowledged tracking weapons in an active warzone has obvious challenges.

“There are always going to be things you don’t know that are happening and you don’t see,” Kahl said. “But we are not seeing any evidence of systemic diversion of the equipment the United States has provided.”