Russian Offensive Campaign Assessment, April 4

April 4, 5:30 pm ET

Russian forces continue to make little to no progress in frontal assaults to capture Donetsk and Luhansk Oblasts, their current main effort of the war. Russian units in Donbas face growing morale and supply issues. Additionally, the Ukrainian defenders of Mariupol have outperformed ISW’s previous estimates and continue to hold the city. Russian efforts to generate replacements from reservists and feed damaged units from northeastern Ukraine into frontal assaults in eastern Ukraine are unlikely to increase their chances of success.

However, Russian forces advancing from the Kharkiv axis are setting conditions to resume offensive operations through the city of Slovyansk to link up with other Russian forces in Donbas and encircle Ukrainian defenders. Russian forces captured Izyum (southeast of Kharkiv) on April 1 and have conducted active preparations to resume offensive operations for the past three days—stockpiling supplies, refitting damaged units, repairing the damaged bridge in Izyum, and conducting reconnaissance in force missions toward the southeast. Russian forces will likely begin offensive operations towards Slovyansk, 50km southeast of Izyum, in the coming days.

Efforts by Russian forces advancing from Izyum to capture Slovyansk will likely prove to be the next pivotal battle of the war in Ukraine. Russian forces likely intend to cut off Ukrainian forces in eastern Ukraine and will need to take Slovyansk as their minimum step to do so. If Russian forces take Slovyansk, they will then have the option to advance directly east to link up with Russian forces fighting in Rubizhne—a shorter drive that will not isolate many Ukrainian forces—or advance toward Horlivka and Donetsk to attempt a wider encirclement of Ukrainian forces. Both options could enable at least limited Russian breakthroughs in Luhansk Oblast. If Russian forces are unable to take Slovyansk at all, Russian frontal assaults in Donbas are unlikely to independently breakthrough Ukrainian defenses and Russia’s campaign to capture the entirety of Luhansk and Donetsk oblasts will likely fail.

Degraded Russian forces in northeastern Ukraine continued to withdraw to Russia and are unlikely to be effective elsewhere, despite ongoing Russian efforts to redeploy them to eastern Ukraine. Ukrainian forces are conducting operations to clear Russians left behind in the withdrawal, and Russian forces are unlikely to hold any cohesive defensive positions. The Ukrainian military reported that elements of Russian VDV (Airborne) units withdrawn from northern Kyiv flew to Belgorod, Russia, on April 4. These units are understrength, missing equipment, and likely highly demoralized. Russian servicemen from the Kyiv axis ordered to renter combat operations may desert or refuse orders, which has occurred in several Russian units throughout the war—including several units that had not yet entered combat.

Key Takeaways

• Russian forces in Izyum are setting conditions to begin offensive operations southeast toward Slovyansk in the coming days to link up with other Russian forces in Donbas and encircle Ukrainian defenders.
• Russian forces in Donetsk and Luhansk Oblasts continue to make little to no progress and face mounting casualties and declining morale. Replacements and reinforcements from northeastern Ukraine are highly unlikely to meaningfully change the balance of forces.
• Efforts by Russian forces advancing from Izyum to capture Slovyansk and threaten Ukrainian forces in Donbas with encirclement will likely prove to be the next pivotal battle of the war in Ukraine. If Russian forces are unable to take Slovyansk, Russia’s campaign to capture the entirety of Luhansk and Donetsk oblasts will likely fail.
• The defenders of Mariupol have outperformed ISW’s previous estimates, and Russian forces are likely taking heavy casualties in ongoing efforts to capture the city.
• Ukrainian forces likely conducted successful counterattacks in Kherson Oblast in the last 24 hours.
• Russian forces have almost completely withdrawn from Chernihiv and Sumy oblasts and will likely completely vacate these regions in the coming days.
• Russian forces withdrawn from the Kyiv axis are highly unlikely to be effectively deployed elsewhere in Ukraine and are likely a spent force.

Russian forces already deployed to the Kremlin’s main effort in eastern Ukraine are highly demoralized and do not have a cohesive command structure. The Ukrainian General Staff reported on April 4 that Russian forces are attempting to create an operational group and expand control structures to “prepare for an offensive operation in eastern Ukraine” and are continuing to deploy additional forces to eastern Ukraine.[1] Russian officers will struggle to develop a new command structure from highly damaged units while simultaneously attempting to continue offensive operations. The Ukrainian General Staff reported on April 4 that losses of the 33rd, 255th, and 294th Motor Rifle Regiments of the 20th Motor Rifle Division (part of the 8th Combined Arms Army and likely active in fighting in Donbas or Mariupol) amounted to up to 40% of equipment and personnel, and surviving servicemen are attempting to leave the military.[2] Ukraine’s Military Intelligence Directorate (GUR) separately reported that it acquired a document signed by Deputy Southern Military District commander Pyotr Gibert indicating that Russian officers are compensating their troops with the promise of additional leave days due to the inability to pay promised monthly salaries in cash.[3]

Russian efforts to generate reserves and replace officer casualties continue to face serious challenges. The Ukrainian General Staff stated that the Russian military is deploying students and educators at higher military educational institutions directly to Ukraine to replace mounting officer casualties.[4] The deployment of untrained officers—and more crucially educational staff—to the war in Ukraine will impede the Russian military’s ability to develop its next generation of officers for years to come. The General Staff additionally reported on April 4 that the Kremlin began “hidden mobilization” measures to send approximately 60,000 personnel to Ukraine.[5] The General Staff stated the Kremlin is prioritizing reservists of all ranks who already have combat experience, particularly in Krasnodar Krai, Perm Oblast, the Dagestan Republic, Ingushetia, and Kalmykia.

We do not report in detail on the deliberate Russian targeting of civilian infrastructure and attacks on unarmed civilians, which are war crimes, because those activities are well-covered in Western media and do not directly affect the military operations we are assessing and forecasting. We will continue to evaluate and report on the effects of these criminal activities on the Ukrainian military and population and specifically on combat in Ukrainian urban areas. We utterly condemn these Russian violations of the laws of armed conflict, Geneva Conventions, and humanity even though we do not describe them in these reports.

ISW has updated its assessment of the four primary efforts Russian forces are engaged in at this time:

• Main effort—Eastern Ukraine (comprised of two subordinate supporting efforts);
• Supporting effort 1—Kharkiv and Izyum;
• Supporting effort 2—Southern axis;
• Supporting effort 3—Sumy and northeastern Ukraine.

Main effort—Eastern Ukraine

Subordinate main effort—Mariupol (Russian objective: Capture Mariupol and reduce the Ukrainian defenders)

The defenders of Mariupol have outperformed ISW’s previous estimates, and Russian forces are likely taking heavy casualties in ongoing efforts to capture the city. The Ukrainian General Staff reported Russian forces continued efforts to take Mariupol with heavy air and artillery support on April 2.[6] The information environment in Mariupol remains poor and ISW cannot independently verify any territorial changes in the last 24 hours.

Subordinate main effort—Donetsk and Luhansk Oblasts (Russian objective: Capture the entirety of Donetsk and Luhansk Oblasts, the claimed territory of Russia’s proxies in Donbas)

Ukrainian forces continued to repel Russian assaults in Donetsk and Luhansk Oblasts on April 3. The Ukrainian General Staff reported that Ukrainian forces repelled seven Russian attacks in the past 24 hours.[7] Russian operations in Luhansk Oblast remain concentrated on Popasna and Rubizhne.[8] Local Ukrainian authorities and Russian forces shared footage confirming ongoing urban fighting in Rubizhne, which the LNR previously falsely claimed to have captured on April 3.[9] Russian forces likely intend to capture Rubizhne before driving west to link up with planned Russian advances southeast from Izyum, discussed below.

Supporting Effort #1—Kharkiv and Izyum: (Russian objective: Advance southeast to support Russian operations in Luhansk Oblast; and fix Ukrainian forces around Kharkiv in place)

Russian forces around Kharkiv continued to shell the city and attempt to fix Ukrainian forces in place.[10] The Ukrainian General Staff stated on April 4 Russian forces additionally prioritized strengthening air defenses around Belgorod, Russia—the main Russian logistics base for the Kharkiv/Izyum axis.[11] Russian forces withdrawn from the Sumy axis are currently reconstituting in Belgorod prior to redeployment to the Izyum or Donbas axes. Russian forces will likely fully withdraw from Sumy Oblast in the coming days, exposing the western flank of Russian positions around Kharkiv. Ukrainian forces will likely increasingly conduct counterattacks in the Kharkiv area, forcing Russian forces to switch their objective from fixing Ukrainian forces in place to defending their lines of communication in the area. 

Russian forces in Izyum continued to set conditions on April 4 to resume major offensive operations southeast toward Slovyansk, 50km southeast of Izyum. The Ukrainian General Staff reported that Russian forces in Izyum, including the Russian 237th Tank Regiment and 752nd Motor Rifle Regiment (of the 3rd Motor Rifle Division) are restoring combat capabilities and repairing the bridge across the Siverskyi Donets River, which runs through the center of Izyum.[12] The Ukrainian General Staff reported a Russian tank company conducted a reconnaissance in force in Brazhivka (south of Izyum) on April 4.[13] Social media users additionally observed a column of Russian equipment redeploying from Kupyansk to Izyum on April 4.[14]

Russian forces likely intend to cut off Ukrainian forces in eastern Ukraine and will need to take Slovyansk as their minimum step to do so. Local Slovyansk and Donetsk authorities called on Slovyansk residents to leave the region on April 4 and stated Russian forces will likely approach the city from Izyum.[15] If Russian forces take Slovyansk, they will then have the option to advance directly east to link up with Russian forces fighting in Rubizhne—a shorter drive that will not isolate many Ukrainian forces—or advance toward Horlivka and Donetsk to attempt a wider encirclement of Ukrainian forces.

Supporting Effort #2—Southern axis: (Objective: Defend Kherson against Ukrainian counterattacks)

The Ukrainian General Staff claimed Ukrainian forces conducted successful counterattacks and retook territory in Kherson Oblast on April 4, though ISW cannot independently verify these attacks or their possible gains.[16] The Ukrainian General Staff previously reported at midnight local time on April 3 that Russian forces prioritized strengthening defensive positions around Kherson and sought to resume offensive operations to capture the entire oblast.[17] Russian attacks in Kherson Oblast in late March and early April were likely intended to regain favorable defensive terrain around Kherson, rather than being attempts to restart major offensive operations toward Mykolayiv.[18] Russian forces in northern Kherson Oblast shelled Ukrainian positions in Novovorontsovka and Maryanske on April 4 but did not conduct any offensive operations towards Kryvyi Rih.[19]

Supporting Effort #3—Sumy and Northeastern Ukraine: (Russian objective: Withdraw combat power in good order for redeployment to eastern Ukraine)

The disorderly withdrawal of Russian forces from northeastern Ukraine makes precise assessments of the situation in Kyiv, Chernihiv, and Sumy oblasts difficult. There are likely no organized Russian defensive positions in those oblasts, and Ukrainian forces are conducting operations to clear Russians left behind in the withdrawal. We will not attempt to map those clearing operations or track their precise locations. Ukrainian forces may already have regained control of more of Chernihiv and Sumy oblasts than we depict, but we do not yet have sufficient evidence to adjust our assessed areas of advance beyond those shown in the accompanying maps. The situation will likely clarify over the next few days, and we will adjust our maps and written assessments accordingly.

Russian forces withdrawn from the Kyiv axis are highly unlikely to be effectively deployed elsewhere in Ukraine and are likely a spent force. Ukrainian forces control the entirety of Kyiv and Zhytomyr oblasts as of April 4, though the Ukrainian General Staff warned that Russian aircraft based in Belarus will likely continue to strike targets around Kyiv.[20] The Ukrainian General Staff reported at midnight local time on April 3 that Russian forces are regrouping in Belarus, and several VDV units, likely from the 76th Airborne Division, are deploying to Belgorod via transport aircraft.[21] These units are understrength, missing equipment, and likely highly demoralized. Russian servicemen from the Kyiv axis ordered to renter combat operations may desert or refuse orders, which has occurred in several Russian units throughout the war—including several units that had not yet entered combat. Russian efforts to use this spent force in combat operations will likely fail.

Russian forces have almost completely withdrawn from Chernihiv and Sumy Oblasts and will likely completely vacate these regions in the coming days. The Ukrainian General Staff reported on April 4 that Russian units from the Central Military District continued to withdraw from Chernihiv city, and Ukrainian forces recaptured several towns in Chernihiv Oblast.[22] The head of Sumy’s regional administration stated on April 4 that there are “almost no [Russian] troops in the Sumy region” and Ukrainian forces are clearing the region of ”single units [and] small groups of Russian forces,” but ISW cannot independently confirm full Ukrainian control of these oblasts to the Russian border.[23]

Immediate items to watch

• Russian forces will likely complete their withdrawal from Kyiv along the Sumy axis in the coming days and will probably abandon their remaining positions around Konotop and Sumy thereafter.
• Russian troops around Kharkiv will likely continue to focus on supporting the shift of the main effort via Izyum toward the southeast and may pull back from the immediate environs of the city.
• Russian and proxy forces will attempt to increase the scope and scale of offensive operations to complete the linkup between the Kharkiv-Izyum axis and occupied Luhansk.
• Russian forces will likely secure Mariupol in coming days, and may attempt to launch renewed offensive operations northwest from the city in an effort to seize Donetsk Oblast.