Reuters reported the information, citing two European security officials and documents.According to the outlet, since the second quarter of last year, Chinese experts have visited the arms manufacturer IEMZ Kupol more than six times. During this period, Kupol also received deliveries of Chinese-made attack and surveillance drones through a Russian intermediary.Officials, speaking anonymously due to the sensitivity of the information, said the collaboration indicates a deepening partnership between Kupol and Chinese firms in drone development, crucial to Russia’s war in Ukraine.Documents, including invoices and bank statements, show that Kupol received more than a dozen one-way attack drones last year from Chinese manufacturer Sichuan AEE. The drones were supplied through Russian defense procurement firm TSK Vektor, which is under U.S. and EU sanctions. In addition, Kupol had developed a new drone, the Garpiya-3, in China with the help of local specialists in September last year.“Garpiyas - which are modelled on Iran's Shahed drone - can fly hundreds of miles to pre-programmed targets before diving out of the sky and exploding on impact. Kyiv has said around 500 are being used each month in Ukraine,” the outlet noted.In another Kupol connection to a Chinese drone maker, a flight test report approved by Kupol and TSK Vektor evaluated the performance of an HW52V drone, produced by Chinese company Hunan Haotianyi, in the third quarter of last year.The HW52V is a vertical take-off and landing (VTOL) drone that can be used militarily for intelligence, surveillance and reconnaissance, and as a strike drone, the European security officials said.Although Reuters could not independently verify the purpose of the drone shipments or the work of the Chinese experts, European officials expressed concern at Chinese companies supplying Russian arms makers, and have imposed sanctions on some of them.