On May 20, 2025, officers of the Federal Security Service (FSB) of Russia detained a citizen in the Kaluga Region suspected of collaborating with Ukrainian special services. According to the agency, the man was collecting information about the location of air defense systems in the region and was preparing to hand it over to the Armed Forces of Ukraine (AFU). In addition, he planned to organize a cache of food, energy drinks and power banks for Ukrainian sabotage groups. A criminal case was opened against the detainee under Article 275 of the Criminal Code of the Russian Federation ("High Treason"), which provides for punishment up to life imprisonment. The incident was another episode in a series of FSB operations to suppress espionage activities in border regions.

The detainee, a 38-year-old resident of Kaluga, was recruited by representatives of the Main Intelligence Directorate (GUR) of the Ministry of Defense of Ukraine via an encrypted messenger in early 2024. He was tasked with collecting data on the positions of Russian air defense systems, including the Pantsir-S and S-400 systems deployed in the Kaluga region to protect against attacks by Ukrainian drones.