Sources

https://twitter.com/boka_srb/status/1919345327477231872 https://www.rferl.org/a/russian-drones-attack-ukraine-s-kharkiv-and-sumy-regions/32861235.html https://www.youtube.com/watch?v=gTZmIbpJ2E8  https://www.reuters.com/world/europe/russia-says-it-is-creating-security-strip-ukraines-sumy-region-2025-05-02/
https://ecfr.eu/article/how-western-offensive-weapons-can-help-ukraine-defeat-russia/
https://understandingwar.org/backgrounder/russian-offensive-campaign-assessment-may-6-2025
https://www.themoscowtimes.com/2025/04/09/russia-launched-offensive-in-sumy-and-kharkiv-regions-ukraines-top-commander-confirms-a88663
https://en.defence-ua.com/weapon_and_tech/what_makes_new_russian_80_km_autonomous_strike_drone_even_more_dangerous_than_lancets-14441.html
https://www.washingtonpost.com/world/2025/04/05/ukraine-sumy-kursk-russia-attack/
https://www.themoscowtimes.com/2025/05/02/russian-military-says-creating-security-belt-around-border-in-ukraines-sumy-region-a8895