Kremlin's Fortress Belt Plan "Significantly Disrupted' By Ukraine's Vivaldi Operation

As more comes out about Ukraine's Operation Vivaldi, it has become apparent not just that the Russians are being pushed back around Lyman - and continue to be - but that this has been going on for months, has essentially disrupted, for at least this year, the Kremlin Fortress Belt attack plan, which thus throws off Putin's entire invasion concept. JL

The Institute for the Study of War reports:

Ukraine's Operation Vivaldi has achieved the operationally-significant objective of disrupting the Russian effort to conduct a wide encirclement of Ukraine’s Fortress Belt. Ukraine’s gains thus far north of Lyman have rendered unfeasible the already-unrealistic Russian plan to encircle the Fortress Belt from the north and south. Russian forces also lost positions south of Lyman and are struggling to recapture positions within Lyman itself because of the Ukrainian advances. These Ukrainian gains were only the first phase of Operation Vivaldi and that Ukrainian forces will continue the operation. Ukrainian forces have likely made additional gains beyond what General Biletskyi has reported. The situation for Russian forces continues to deteriorate in the area, including north and south of Kolodyazi.

Ukraine’s Operation Vivaldi has achieved the operationally-significant objective of disrupting the Russian effort to conduct a wide encirclement of Ukraine’s Fortress Belt. Ukraine’s gains thus far north of Lyman have rendered unfeasible the already-unrealistic Russian plan to encircle the Fortress Belt from the north and south. The prominent Kremlin-affiliated Russian milblogger agreed with ISW’s assessment, acknowledging that Ukraine’s successes will delay Russia’s offensive on Slovyansk — the Russian objective after the seizure of Lyman itself.[10] The milblogger warned that the northern flank of the Russian Southern Grouping of Forces (operating in the area southeast of Lyman and east of Kramatorsk) is now vulnerable to Ukrainian counterattacks and interdiction efforts. The milblogger stated that Russian forces also lost positions south of Lyman and are struggling to recapture positions within Lyman itself because of the Ukrainian advances. Russian milbloggers continue to blame the culture of “beautiful reports,” in which exaggerated claims of Russian advances from battlefield commanders to the higher command impact operational planning, for enabling Ukrainian advances.[11] Another prominent milblogger claimed that some Russian military commanders are attempting to cover up the degree of Russian losses by rapidly forming assault troops of untrained personnel in efforts to recapture territory, but that the higher Russian military command is now aware of the situation on the ground.[12]

Russian forces continue prioritizing attacks aimed at advancing frontally on the Fortress Belt from the south and encircling the Fortress Belt from the southwest over efforts to advance on the cities from the east, even though the Lyman effort has failed.[13] The Russian military command may still be internalizing the loss of the Lyman salient and tactical initiative in the area or may seek to cut Ukrainian ground lines of communication (GLOCs) to the Fortress Belt from the west. The Russian military command also likely seeks to achieve informational effects by continuing to make claimed or actual advances in Donetsk Oblast, Russia’s stated priority effort, that the Kremlin can portray as victories domestically and internationally. Ukraine’s ongoing counteroffensive undermines this Russian cognitive warfare effort, however, and will likely continue to do so as Ukrainian forces continue and later release more information about Operation Vivaldi. 

The Ukrainian military gave its first explicit confirmation of ongoing Ukrainian counteroffensive operations against the Russian salient northwest of Lyman. Ukrainian 3rd Army Corps Commander Brigadier General Andrii Biletskyi confirmed on September 15 that Ukrainian forces have been conducting a counteroffensive — Operation Vivaldi — against the Russian salient north of Lyman.[1] Biletskyi stated that Ukrainian forces have cleared or liberated a total of 85 square kilometers, including liberating Serednie (northwest of Lyman) and clearing Russian infiltrators from Novoselivka (south of Serednie), Yarova (southwest of Novoselivka), Oleksandrivka (west of Serednie), and the outskirts of Korovii Yar (northwest of Serednie). Biletskyi noted that these Ukrainian gains were only the first phase of Operation Vivaldi and that Ukrainian forces will continue the operation. Ukrainian forces have likely made additional gains beyond what Biletskyi has reported, and Russian sources are beginning to acknowledge these gains. Russian forces are shelling Ukrainian positions in Kolodyazi (northeast of Lyman) with tube artillery, according to geolocated footage published on September 15.[2] A prominent Russian milblogger additionally acknowledged that Russian forces are attempting to push Ukrainian forces from Kolodyazi — a coy acknowledgement that Ukrainian forces have likely liberated Kolodyazi in conjunction with the geolocated footage.[3] Russian milbloggers and a source reporting on the Russian Western Grouping of Forces continue to indicate that the situation for Russian forces continues to deteriorate in the area, including north and south of Kolodyazi.[4] The Ukrainian 3rd Army Corps conducted an intermediate-range strike campaign to interdict Russian logistics and degrade fuel supplies as part of Operation Vivaldi. The 3rd Army Corps published an additional video discussing Operation Vivaldi, noting that its drone operators additionally isolated Russian logistics through two stages of strikes: first at depths of up to 50 kilometers from the frontline, then expanding up to 120 kilometers from the frontline.[5] The 3rd Army Corps stated that these Ukrainian strikes forced Russian forces to shut down a pipeline supplying fuel from Russia to occupied Luhansk Oblast; to move support elements of the 144th Motorized Rifle Division (20th Combined Arms Army, Moscow Military District) from occupied Ukraine to Voronezh Oblast; and to disperse Russian fuel and ammunition depots, communications hubs, command posts, and transports, including into Russia and in forests, further inhibiting Russian logistics. Ukrainian forces have been conducting an intermediate-range strike campaign against Russian logistics, particularly tanker trucks and fuel depots, against areas throughout occupied Ukraine since Spring 2026.[6] The 3rd Army Corps campaign against occupied Luhansk Oblast appears to have run concurrently and in conjunction with other strike campaigns, including by Ukraine’s Unmanned Systems Forces. The 3rd Army Corps report corroborates many statements from a source reporting on the Russian Western Grouping of Forces that Russian forces, particularly the 144th Motorized Rifle Division and its subunits, have been struggling with logistics in the Borova and Lyman directions due to Ukraine’s strike campaign into occupied Luhansk Oblast.[7] Ukrainian forces have continued their intermediate-range strike campaign against both occupied Luhansk Oblast in the east and areas of occupied southern Ukraine, and these strikes will likely continue to enable Ukraine to achieve operational effects on the battlefield.[8] Russian forces will likely continue to struggle defending against these strikes as they have thus far because of their air defense and manpower constraints.[9]