Ukrainian military intelligence and allied hacker groups said they carried out a large-scale cyberattack against a major Russian drone supplier, disrupting its operations.

In a statement on Telegram, two well-known Ukrainian volunteer hacker groups — the Ukrainian Cyber Alliance (UAC) and Black Owl (BO Team) — claimed to have accessed and destroyed terabytes of technical data from Gaskar Group, a Russian developer and manufacturer of unmanned aerial vehicles, including those reportedly used to attack Ukraine.

Ukraine’s military intelligence agency (HUR) confirmed the attack and its involvement in a statement sent to local media. The agency claimed that the operation had paralyzed Gaskar’s accounting systems, production software and internet infrastructure.

The stolen data — including drone design documents, source code and employee records — was handed over to Ukraine’s defense forces, HUR said.

The Ukrainian Cyber Alliance published samples of the stolen data online, including what it said were scans of employee passports. The hackers also claimed the attack affected the company’s building security system, forcing staff to trigger the fire alarm to unlock doors.

As a result of the attack, “thousands of drones won’t be reaching the front lines anytime soon,” UAC said.

Recorded Future News could not independently verify the claims, and Gaskar Group did not immediately respond to a request for comment.

In a statement to Russian news channel EG — which has been labeled a “foreign agent” by Moscow — Gaskar Group said there had been “an attempted attack” on the company but that it continues to operate normally and its facilities have not stopped working.

The reported operation is the second such incident targeting Russia’s drone industry this month. Earlier in July, Russian developers of firmware used to convert commercial drones for battlefield use said their distribution servers were breached, briefly disabling systems and displaying fake messages on operator terminals. The firmware itself was not compromised, the developers said.

BO Team and the Ukrainian Cyber Alliance have previously been linked to high-profile cyberattacks on Russian state infrastructure. Last year, a BO Team attack on Russia’s national court database reportedly wiped out a third of its digital case archive, while a UAC operation disrupted parking enforcement systems in the city of Tver.

In a recent report, Russian cybersecurity firm Kaspersky described BO Team as a “major threat” to Russian state institutions and critical infrastructure.

BO Team has previously collaborated with Ukrainian military intelligence in operations against Russian entities, including the ruling United Russia party and a Russian scientific research center.