Ukraine’s Special Operation Forces (SSO) said it detected and destroyed a Russian S-400 air defense missile complex in Russia’s Kaluga region on Sept. 5. The S-400 system (NATO: SA-21 “Growler”), an analogue to the US’s Patriot system with a range up to 380 km (240 miles), is one of the more advanced systems in Russian service apart from the S-500 systems that entered service in 2021. A 2023 Newsweek article estimated that each S-400 system costs around $200 million, citing an expert from the Royal United Services Institute think tank. The Kaluga region borders Russia’s Bryansk region, with the latter located on Ukraine’s northeastern border and has been subject to Ukrainian attacks – including ground incursions. While the SSO did not specify the weapons used, Russia’s Ministry of Defense claimed to have downed 11 Ukrainian drones over the Kaluga region overnight between Sept. 4 and Sept. 5.