China-made engines are being shipped secretly to Russian state-owned drone manufacturer IEMZ Kupol to boost production of anti-Ukraine drones, Reuters reported Thursday, citing three European security officials and documents reviewed by the news agency.

The Chinese shipments, labeled as "industrial refrigeration units" to avoid Western sanctions, are used to increase production of the Garpiya-A1 attack drone, the report said.

Kupol has been manufacturing the drones using Chinese hardware, including L550E engines manufactured by Xiamen Limbach Aviation Engine, according to a Reuters report in September 2024.

Following the report, the EU and the US sanctioned the companies involved in drone making, Reuters said.

After the sanctions, a new Chinese firm, Beijing Xichao International Technology and Trade, has started supplying the L550E engines, Reuters reported, citing invoices, an internal letter by Kupol, and transportation documents.

Kupol raised its production of drones to more than 6,000 this year from 2,000 in 2024, the report said.

The drones are launched at civilian and military targets deep into Ukraine's territory, with about 500 used by Russia per month, the report said.