Russian Offensive Campaign Assessment, Dec. 15, 2025

Toplines
US, Ukrainian, and European officials reportedly agreed on unspecified security guarantees for Ukraine during a peace negotiation meeting in Berlin, Germany, on December 15. Ukrainian President Volodymyr Zelensky, Ukrainian Defense Council Secretary Rustem Umerov, US Special Envoy to the Middle East Steve Witkoff, and former Senior Advisor to the US President Jared Kushner met in Berlin, Germany, on December 15 to continue negotiations for a prospective peace deal to end Russia’s war in Ukraine.[1] Two US officials told the New York Times (NYT) on December 15 that the United States, Ukraine, and Europe agreed on a “NATO-like” security guarantee for the future security of Ukraine.[2] The US officials stated that the majority of the December 14 to 15 negotiations pertained to security guarantees, although the officials did not elaborate on specifics. The Kremlin has consistently indicated that it will reject any peace deals that offer reliable security guarantees for Ukraine, and is highly unlikely to accept a settlement that contains any provisions safeguarding Ukrainian territorial integrity.[3] The Kremlin notably effectively rejected the provision of reliable security guarantees for Ukraine as outlined in the US-proposed 28-point peace plan.[4]
Zelensky stated on December 15 that discussions concerning territorial issues are ongoing, and the two US officials cited by NYT reported that Zelensky and Russian President Vladimir Putin will likely need to discuss and decide upon the matter of territorial agreements themselves.[5] Putin has consistently declined to meet with Zelensky, including during the lead up to the full scale invasion and during several subsequent iterations of peace negotiations.[6] Russia has previously attempted to secure untenable territorial concessions from Ukraine that include Ukraine’s Fortress Belt, the fortified defensive line in Donetsk Oblast that has served as the backbone of Ukraine’s defenses since 2014.[7] Ukraine’s concession of its most valuable defense line into the hands of the Kremlin would provide Russia with more advantageous positions to renew aggression against southwestern and central Ukraine in the future.[8] ISW continues to assess that Russia will use political and military means to achieve its stated goal of seizing all of Ukraine and that Russia is therefore unlikely to accept a peace deal or security guarantees that do not grant full Russian control of Ukraine in the intermediate to long term future.[9]
Ukrainian forces conducted an unmanned underwater vehicle (UUV) strike against a Russian submarine for the first time in naval history on the night of December 14 to 15. The Ukrainian Security Service (SBU) published footage on December 15, which was later geolocated, showing Ukrainian “Sub Sea Baby” UUVs strike a Russian Project 636 Varshavyanka-class (NATO Kilo-class) submarine docked at the Novorossiysk Naval Base in Krasnodar Krai, causing explosions and critical damage to the submarine.[10] The SBU noted that the submarine was equipped with four Kalibr cruise missile launchers that Russia used to strike Ukraine and that the damage may have forced Russian forces to stop operating the submarine. Planet Labs satellite imagery captured on December 5 shows that two Kilo-class submarines were present at the Novorossiysk Naval Base as of December 5, and lower-resolution imagery captured on December 11 indicates that at least one Kilo-class submarine was present at the base as of December 11. National Aeronautics and Space Administration Fire Information for Resource Management System (NASA FIRMS) data published on December 15 indicates that there were fires near the Novorossiysk Naval Base.[11] Russian forces previously docked Kilo-class submarines in occupied Crimea and the Sevastopol port but began withdrawing them from the western Black Sea and transferring them to Novorossiysk in October 2023 due to a successful Ukrainian strike campaign against Russian Black Sea Fleet assets.[12] Russia uses Kilo-class submarines to conduct Kalibr cruise missile strikes against Ukraine, primarily Odesa Oblast, and the Ukrainian strike likely intended to degrade Russia’s ability to target Odesa Oblast with Kalibr missiles. Ukraine’s strike against the Kilo-class submarine in Novorossiysk shows that Ukrainian forces continue to modernize and optimize their unmanned capabilities such that Ukraine can strike Russian military targets at a range that Russian forces previously thought safe.
Ukrainian forces continue counterattacking in the Kupyansk direction as Russian ultranationalist milbloggers acknowledge the severity of the situation for Russian forces. Ukrainian Joint Forces Group Spokesperson Colonel Viktor Trehubov reported on December 15 that Ukrainian forces continue clearing operations within Kupyansk and are avoiding engaging in urban combat, and that Russian forces are using unmanned aerial vehicles (UAVs) to supply the grouping of around 100 to200 Russian personnel left within Kupyansk.[13] Trehubov implied that the Russian forces’ logistical situation is complicated in Kupyansk because UAVs have a limited carrying capacity, cannot fly over certain areas, and occasionally drop supplies in a way that exposes Russian positions to Ukrainian forces. A non-commissioned officer (NCO) of a Ukrainian brigade operating in the Kupyansk direction reported that Ukrainian forces have liberated several settlements and nearby forest areas, and that elements of his brigade are operating within northern Kupyansk.[14] The NCO stated that Russian forces continue attempting infiltration missions to reinforce positions in Kupyansk through a gas pipeline, but that Ukrainian forces have blocked the pipeline and have all possible egress points under fire control. Geolocated footage published on December 14 and 15 indicates that Russian forces likely do not hold positions within Petropavlivka (east of Kupyansk), contrary to Russian claims of advances in the area.[15]
Russian milbloggers continued to acknowledge that the situation for Russian forces in Kupyansk is deteriorating.[16] A milblogger claimed that Russian forces hold some positions in northern and central Kupyansk but that the rest of the city is either a contested “gray zone” or Ukrainian held.[17] Another milblogger claimed that the situation for Russian forces in western Kupyansk is rapidly worsening; that elements of the Russian 68th Motorized Rifle Division (6th Combined Arms Army [CAA], Leningrad Military District [LMD]) are “desperately fighting” and acknowledged that Ukrainian forces advanced within Kupyansk and Myrove (immediately northwest of Kupyansk).[18] The milblogger claimed that Russian forces no longer have manpower superiority in the area and that Ukrainian interdiction efforts are hindering Russian operations. The milblogger stated that Ukrainian gains in Kupyansk have forced Russian drone operators to withdraw from the area to the east (left) bank of the Oskil River. The Kremlin has been leveraging claims of advances in and near Kupyansk for a cognitive warfare effort designed to portray the Ukrainian lines as on the verge of collapse such that Ukraine and the West should concede to Russia’s demands, and the Ukrainian counterattacks in the Kupyansk direction continue to demonstrate that.[19]
Russian forces are striking Ukrainian logistics lines in Odesa Oblast with various air launched munitions, including glide bombs, highlighting Ukraine’s urgent need for a well provisioned and diverse air defense umbrella. Geolocated footage published on December 15 shows Russian long range drones and glide bombs striking a bridge on the P-70 Odesa City- Bilhorod-Dnistrovskyi highway over the Dneister River in Zatoka, Odesa Oblast, on December 14.[20] Russian milbloggers claimed on December 14 that Russian forces struck a railway bridge near Zatoka with glide bombs and Geran (Shahed) drones, and a Kremlin-affiliated milblogger claimed on December 15 that the Russian strikes completely destroyed the bridge.[21] Additional geolocated footage published on December 15 shows Russian drones striking the Odeska railway bridge over the Sarata River in southern Sarata, Odesa Oblast.[22] Russian forces have recently intensified strikes against Odesa Oblast in parallel with intensified Kremlin rhetorical threats.[23] The Russian use of glide bombs as part of their strike packages against Odesa Oblast is notable, as they allow Russian forces to cause damage to Ukrainian logistical infrastructure with relatively cheaper munitions.[24] Russian forces must still use expensive manned aircraft to launch these glide bombs, which makes the aircraft vulnerable to the threat of Ukrainian air defenses, forcing Russia to weigh the balance of using cheaper munitions at the expense of its more exquisite aircraft systems. The increase in guided glide bomb attacks against Odesa Oblast highlights the fact that Ukraine urgently needs a holistic air defense umbrella that allows it to down manned aircraft, missiles, and drones alike.
Russian strikes appear to be advancing the Kremlin’s stated goal of degrading Ukraine’s energy infrastructure by splitting Ukraine’s power grid in half. Ukraine requires Western-provided air defense systems and partner support for its drone interceptor development to safeguard itself against increasingly devastating strikes on its energy infrastructure. Several people familiar with the situation told the Washington Post on December 15 that Russian strikes threaten to completely disable transmission systems that move electricity from the western half of Ukraine, which stores most of Ukraine’s electricity, to eastern Ukraine.[25] The Washington Post‘s sources noted that Russian strikes could effectively split Ukraine’s energy grid into two parts along an east-west divide. ISW previously reported on Russian efforts to generate a west-east split in the Ukrainian power grid.[26] An anonymous senior European diplomat told the Washington Post that eastern Ukraine is “at the brink” of a complete blackout, and another person familiar with the energy crisis stated that Kyiv City may also suffer a full blackout. The European diplomat also stated that Russian forces are attempting to create energy islands in individual Ukrainian oblasts, effectively cutting off individual regions from any electricity generation, deliveries, and transmission systems. A spokesperson for Ukraine’s energy grid operator Ukrenergo told the Washington Post that Russian forces launched eight massive, combined missile and drone strikes against Ukrainian energy infrastructure between October and December 2025, particularly targeting electricity and distribution infrastructure. Ukrainian energy expert Volodymyr Omelchenko stated that Russian forces launch regular combined strikes every seven to 10 days to maximize energy deficits and target infrastructure that is undergoing repairs after the previous strike.[27] Omelchenko noted that Russian forces are constantly targeting energy distribution infrastructure in Chernihiv, Sumy, Kharkiv, Kherson, and Odesa oblasts.
Russian forces launched 9,298 drones and 270 missiles in October 2025, 5,444 drones and 216 missiles in November 2025, and 2,757 drones and 91 missiles in December 2025 as of December 15.[28] ISW has previously observed reports that Russian forces are engaging in a large-scale strike campaign that targets one or two specific regions in quick succession to degrade Ukraine’s ability to repair energy infrastructure rapidly.[29] Russian forces also focus on targeting different elements of Ukraine’s energy infrastructure, including substations, to systematically destroy the entire Ukrainian energy ecosystem and complicate Ukraine’s ability to treat targeted areas, elongating periods without power.[30] ISW continues to assess that Russia‘s increasingly large strike packages highlight the critical importance of Western assistance in bolstering Ukraine’s air defense capabilities, particularly with subsidies for Ukrainian programs that focus on air defense innovations such as Ukraine’s drone interceptor programs.
Russian Main Effort: Eastern Ukraine
Russian Subordinate Main Effort #1
Russian objective: Push Ukrainian forces back from the international border with Belgorod Oblast and approach to within tube artillery range of Kharkiv City.
Ukrainian forces recently maintained positions or advanced in northern Kharkiv Oblast.
Refinement of area under Russian claims: Geolocated footage published on December 14 indicates that Ukrainian forces maintain positions or recently advanced in western Vovchanski Khutory – an area where Russian sources previously claimed that Russian forces maintained a presence.[39]
Russian forces attacked northeast of Kharkiv City near Vovchansk, Vovchanski Khutory, Synelnykove, Prylipka, Lyman, and Vilcha on December 14 and 15.[40] A Russian milblogger reportedly affiliated with the Russian Northern Grouping of Forces claimed that Ukrainian forces counterattacked near Lyman.[41]
Order of Battle: Drone operators and other elements of the Chechen Zapad-Akhmat Battalion, the 128th Motorized Rifle Brigade (44th Army Corps [AC], Leningrad Military District [LMD]), and of the Chechen Kurchaloyevsky Raion Russian Ministry of Internal Affairs (MVD) department are reportedly operating near Vovchansk.[42]
Russian forces continued offensive operations east of Velykyi Burluk toward Obukhivka and southeast of Velykyi Burluk toward Kolodyazne on December 14 and 15 but did not advance.[43]
Russian Subordinate Main Effort #2
Russian objective: Capture the remainder of Luhansk Oblast and push westward into eastern Kharkiv Oblast and encircle northern Donetsk Oblast
Russian forces continued offensive operations in the Kupyansk direction on December 15 but did not advance.
See topline for more information on recent Ukrainian advances in the Kupyansk direction.
Assessed Russian infiltrations: Geolocated footage published on December 15 shows Russian forces operating in eastern Kurylivka (southeast of Kupyansk) during what ISW assesses was a Russian infiltration mission that did not change the control of terrain or the forward edge of battle area (FEBA).[44]
Unconfirmed claims: A Russian milblogger claimed on December 15 that Russian forces advanced in eastern Kurylivka and south of Pishchane (both southeast of Kupyansk).[45]
Russian forces attacked near and within Kupyansk itself; east of Kupyansk toward Petropavlivka; and southeast of Kupyansk toward Pishchane on December 14 and 15.[46] A Russian milblogger claimed that Ukrainian forces counterattacked from Myrove and Radkivka (northwest of Kupyansk) and Sobolivka (southwest of Kupyansk).[47]
Order of Battle: Elements of the Russian 121st Motorized Rifle Regiment (68th Motorized Rifle Division, 6th Combined Arms Army [CAA], Leningrad Military District [LMD]) are striking Ukrainian positions in northeastern Petropavlivka.[48] Elements of the 68th Motorized Rifle Division (6th CAA), including its 122nd Motorized Rifle Regiment, and of the 27th Motorized Rifle Brigade (1st Guards Tank Army [GTA], Moscow Military District [MMD]) and Rubikon Center for Advanced Unmanned Technologies are operating within and near Kupyansk.[49]
Russian forces attacked southeast of Borova near Novoyehorivka on December 14 and 15 but did not advance.[50]
Russian forces continued offensive operations in the Slovyansk-Lyman direction on December 15 but did not advance.
Russian forces attacked near Lyman itself; northwest of Lyman near Novoselivka, Drobysheve, and Serednie; northeast of Lyman near Kolodyazi; and east of Lyman near Zarichne on December 14 and 15.[51]
The spokesperson of a Ukrainian brigade operating in the Lyman direction reported on December 15 that Ukrainian forces retain control of Stavky (north of Lyman) and Novoselivka (northwest of Lyman), but that the Russian forces maintain significant manpower superiority of roughly six to ten Russian servicemembers per one Ukrainian servicemember.[52] The spokesperson stated that Russian forces are attempting to advance despite high personnel losses and are using both drones and aviation to complicate Ukrainian defensive operations.
Order of Battle: Drone operators of the Russian 37th Motorized Rifle Regiment (67th Motorized Rifle Division, 25th CAA, Central Military District [CMD]) are striking Ukrainian objects in western Lyman.[53] 9K55 Grad-1 MLRS crews of the 83rd Propelled Artillery Regiment (25th CAA, CMD) and drone operators of the 144th Motorized Rifle Division (20th CAA, MMD) are reportedly striking Ukrainian forces in the Lyman direction.[54]
Russian Subordinate Main Effort #3
Russian objective: Capture the entirety of Donetsk Oblast, the claimed territory of Russia’s proxies in Donbas, and advance into Dnipropetrovsk Oblast
Russian forces continued offensive operations in the Siversk direction on December 15 but did not make confirmed advances.
Unconfirmed claims: Russian milbloggers claimed that Russian forces advanced north of Svyato-Pokrovske and east of Khromivka (both southwest of Siversk).[55]
Russian forces attacked near and within Siversk; northwest of Siversk near Dronivka and Yampil and toward Ozerne and Zakitne; northeast of Siversk near Serebryanka; south of Siversk near Pereizne; and southwest of Siversk near Vasyukivka and Svyato-Pokrovske and toward Riznykivka on December 14 and 15.[56]
Russian forces recently advanced in the Kostyantynivka-Druzhkivka tactical area.
Assessed Russian advances: Geolocated footage published on December 13 and geolocated on December 14 indicates that Russian forces marginally advanced in southeastern Kostyantynivka.[57]
Russian forces attacked near and within Kostyantynivka; east of Kostyantynivka near Oleksandro-Shultyne; southeast of Kostyantynivka near Pleshchiivka, Kleban-Byk, Shcherbynivka, and Ivanopillya; south of Kostyantynivka near Yablunivka; and southwest of Druzhkivka near Volodymyrivka and Sofiivka and toward Novopavlivka on December 14 and 15.[58]
Order of Battle: Artillery elements of the Russian 85th Motorized Rifle Brigade (3rd Combined Arms Army, formerly 2nd Luhansk People’s Republic Army Corps [LNR AC], Southern Military District [SMD]) are striking Ukrainian positions north of Pazeno (southwest of Siversk).[59] Drone operators of the 242nd Motorized Rifle Regiment (20th Motorized Rifle Division, 8th CAA, SMD) are reportedly striking Ukrainian communications systems near Rusyn Yar (south of Druzhkivka).[60] Elements of the BARS-27 Detachment (Russian Combat Army Reserve) are reportedly operating in the Kramatorsk-Druzhkivka direction.[61]
Russian forces continued offensive operations in the Dobropillya tactical area on December 15 but did not advance.
Russian forces attacked east of Dobropillya near Shakhove and southeast of Dobropillya near Zapovidne on December 14 and 15.[62]
A Russian milblogger claimed on December 15 that drone operators and other elements of the Russian 33rd Motorized Rifle Regiment (20th Motorized Rifle Division, 8th CAA) are using thermal imaging cameras on drones along with the seasonal lack of vegetation in windbreaks near the Dobropillya salient to strike Ukrainian forces with increased accuracy, limiting potential Ukrainian maneuverability.[63] The milblogger acknowledged that Ukrainian forces can also use these conditions to increase their strike accuracy against Russian forces.
Order of Battle: Drone operators of the Aleppo Detachment of the 1472nd Motorized Rifle Regiment (68th AC, Eastern Military District [EMD]) are reportedly striking Ukrainian positions in the Dobropillya direction.[64]
Russian forces continued offensive operations in the Pokrovsk direction on December 15 but did not advance.
Assessed Russian infiltrations: Geolocated footage published on December 15 shows Russian forces operating north of Pokrovsk during what ISW assesses to have been a Russian infiltration mission that did not change the control of terrain or the forward edge of the battle area (FEBA).[65]
Russian forces attacked near and within Pokrovsk; northwest of Pokrovsk near Hryshyne; north of Pokrovsk near Rodynske; east of Pokrovsk near and within Myrnohrad; and southwest of Pokrovsk near Kotlyne, Udachne, and Molodetske on December 14 and 15.[66] A Russian milblogger claimed that Ukrainian forces counterattacked near Hryshyne toward Pokrovsk.[67]
Order of Battle: Drone operators of the Smuglyanka Detachment and of the Rubikon Center for Advanced Unmanned Technologies are reportedly striking Ukrainian positions near Hryshyne.[68] Elements of the BARS-22 (Russian Combat Army Reserve) and 55th Naval Infantry Division (newly formed on the basis of the 155th Naval Infantry Brigade) are reportedly striking Ukrainian positions near Myrnohrad.[69]
Russian forces continued offensive operations in the Novopavlivka direction on December 15 but did not advance.
Russian forces attacked toward Novopavlivka itself and south of Novopavlivka near Filiya, Yalta, and Dachne on December 14 and 15.[70]
Russian forces continued offensive operations in the Oleksandrivka direction on December 15 but did not advance.
Russian forces attacked southeast of Oleksandrivka near Sichneve, Sosnivka, Verbove, Novoselivka, Krasnohirske, and Oleksandrohrad and toward Oleksiivka on December 14 and 15.[71]
Order of Battle: Assault and reconnaissance elements of the Russian 37th Motorized Rifle Brigade and of the 5th Tank Brigade (both 36th CAA, EMD) are reportedly operating in the Oleksandrivka direction.[72]
Ukrainian forces continued their mid-range strike campaign against Russian military assets in occupied Donetsk City. Geolocated footage published on December 15 shows Ukrainian drones striking a Russian ammunition depot in eastern Donetsk City and a Geran drone warehouse at the Donetsk City Airport in northern Donetsk City on December 14.[73]