KYIV, June 23, 2026 — Ukrainian forces have largely halted the Russian Spring-Summer 2026 offensive, with Russian forces gaining a presence in only a fraction of the territory they did in May 2025, according to the latest assessment from the Institute for the Study of War (ISW). The findings suggest a significant shift in the battlefield dynamics as the war enters its fourth year.

ISW observed evidence to assess that Russian forces gained control of or infiltrated 40.64 square kilometers between December 2025 and May 2026. Russian forces, however, lost 281.1 square kilometers in the same time period when only considering territory that Russian forces control. The calculations show that Russian forces lost control of about 281 square kilometers in part due to the fact that ISW recodes areas in the Russian advances layer to infiltrations when new evidence allows reassessment of the level of control Russian forces maintain over an area.

Dramatic Slowdown in Russian Advances

Comparisons of Russia's gains in 2025 with the same period last year show that Russia's gains have slowed significantly, even when including Russian infiltrations. Russian forces advanced into 515.84 square kilometers from December 2024 to May 2025, compared to the 40.64 square kilometers into which they advanced or infiltrated in the same time period in 2025-2026.

Russian forces thus seized or infiltrated into only 7.87 percent as much territory in 2026 as they advanced into in 2025. Russia's year-on-year performance statistics significantly worsen when comparing only areas in which ISW assesses that Russian forces exert control: the 515.84 square kilometers they seized in early 2025 compares poorly with the net loss of 281.1 square kilometers they suffered in the same period this year.

Beyond Weather: Comprehensive Battlefield Shifts

Russia's declining gains appear to be unrelated to the seasonal weather shifts that traditionally hinder advances, but is likely the result of more comprehensive battlefield shifts in 2026. ISW assessed that Russian forces suffered a net loss of territory controlled in April 2026 but that this may have been in part related to annual seasonal patterns. Russia's April 2026 decline may have been related to the muddy rasputitsa season when snow melts and rains degrade conditions for mechanized movement.

Russian forces have historically increased their advances in May and June as the ground dries—as was the case in 2025. Russian gains in May 2026, however, are not following a similar pattern, suggesting that Russia's declining advances in 2026 have not been related to seasonal weather conditions.

Russia's slower advances are likely related to wider changes on the battlefield, including:

• Ukrainian ground counterattacks
• Ukrainian mid-range strikes
• The February 2026 block on Russia's use of Starlink terminals in Ukraine
• The Kremlin's throttling of Telegram

Economic Strain on Russia

Russian President Vladimir Putin is reportedly resisting pressure to reduce defense spending and end his war against Ukraine, despite increased warnings from economic officials about the unsustainable strain his war effort is putting on the Russian economy. Bloomberg reported on June 1, citing sources and documents that Bloomberg viewed, that senior Russian Ministry of Finance and Central Bank officials have told Putin that Russia's current level of projected war spending is on an unaffordable path and risks dangerously widening the budget deficit.

The sources stated that the Russian officials have proposed defense spending cuts, but that some in the Russian Ministry of Defense (MoD) and Kremlin are advocating against reduced defense spending in order to avoid damaging the many businesses that are reliant on military-related contracts. Sources stated that the Russian MoD is even demanding additional funding.

The Russian Ministry of Finance admitted on April 9 that the Russian budget deficit reached 4.58 trillion rubles (roughly $63.5 billion) in the first three months of 2026, already exceeding the planned deficit of 3.79 trillion rubles (roughly $52.5 billion dollars) for all of 2026.

Ukrainian Strikes Deep Inside Russia

Ukraine has intensified its long-range strike campaign against Russian energy and military infrastructure. President Volodymyr Zelensky announced that "for the second time this week, the Moscow oil refinery was hit" by Ukrainian drones, demonstrating Ukraine's growing ability to strike deep inside Russian territory.

Satellite imagery provided more details about recent Ukrainian strikes on Russian oil infrastructure. Imagery published on June 1 shows damage to the Balakhonikhinskaya Oil Pumping Station in Nizhny Novgorod Oblast after a reported Ukrainian drone strike. Additional imagery indicated that Ukrainian strikes on May 29 to 30 damaged at least one of the fuel tanks of the Armavir Oil Depot in Krasnodar Krai.

The Drone War Intensifies

Russian forces conducted a series of long-range drone strikes against Ukraine on the night of May 31 to June 1. The Ukrainian Air Force reported that Russian forces launched 265 Shahed-type, Gerbera-type, and Italmas-type strike drones and Parodiya decoy drones from multiple directions. The Ukrainian Air Force reported that Ukrainian forces downed 228 drones, that 27 drones struck 18 locations, and that debris fell on 12 locations.

Russian forces are increasingly targeting Ukrainian railway infrastructure. Ukraine's state rail company Ukrzaliznytsia reported on June 1 that Russian forces struck railway infrastructure and rolling stock 541 times during the first quarter of 2026, damaging 1,718 railway facilities, causing approximately $178 million in losses, and decreasing freight transportation volumes by 6.4 percent.

What This Means

The ISW assessment suggests that the war is entering a new phase. Ukraine's ability to halt the Russian offensive, combined with its growing capacity to strike deep inside Russia, indicates a shift in the balance of power. However, the war remains a grinding conflict with no immediate end in sight.

Putin's unwillingness to cut defense spending and scale down his war effort suggests that Putin believes that he will be able to win the war in the near to medium term and that the Russian economy is able to hold on until then. However, the economic strain and battlefield setbacks raise questions about how long Russia can sustain its current level of military operations.

For Ukraine, the challenge remains securing continued Western support while building on its battlefield successes. The coming months will be critical in determining whether Ukraine can convert its defensive successes into a more favorable negotiating position or whether the war will continue as a prolonged conflict of attrition.