Weekly Russia-Ukraine war summary: Russian advance in Sumy Region, “old man with Starlink” near Chasiv Yar, record UAV raids on Russia

In this week's summary:

• Russian troops have established effective control over more than 60 square kilometers in the border zone of Ukraine's Sumy region.
• First footage has been published of Ukrainian F-16 fighter jets striking targets in the Kursk sector with guided aerial bombs.
• War blogger Anatoly Radov reported an unexpected problem for the Russian Armed Forces in Stupochky south of Chasiv Yar: “an old man with Starlink.”
• Russian forces have almost eliminated the AFU defensive area in the pocket west of Toretsk.
• A salient threatening Ukrainian defensive positions has formed between Pokrovsk and Kostiantynivka.
• For the first time in 2025, the Russian Armed Forces achieved a weekly territorial advance of more than 100 square kilometers (from May 19-25).
• The Russian Ministry of Defense reported a record number of UAV raids: 2,331 Ukrainian drones were intercepted from the evening of May 20 to the morning of May 27.
• The number of visually confirmed losses of Russian tanks during the war has exceeded 4,000 units, Oryx reports.

Situation at the front

In the Sumy Region, DeepState recognized control by the Russian Armed Forces over a border area of over 60 square kilometers. Russian sources, in turn, reported ( 1, 2, 3 ) the capture of Loknia, Vladymyrivka, Kostiantynivka, and Bilovody, demonstrating the “flag-planting” in the latter locality.

DeepState reported on the approach of the Russian Armed Forces to Yunakivka and the general intensification of Russian assaults in that sector. Ukrainian military engineer Serhii ‘Flash’ Beskrestnov attributes the current successes of the Russian Armed Forces to the use of massive artillery fire with the addition of UAVs. Ukrainian serviceman Stanislav Buniatov points to Russia's extensive use of infantry and challenges with Ukrainian logistics that go all the way back to the withdrawal from Russia's Kursk Region.

Russian pro-war channels also showed burnt vehicles on a road in the Sumy Region, illustrating how difficult it is to create a “buffer zone” in the area. In turn, the Ukrainian side published the first footage of F-16s launching guided aerial bombs at targets, allegedly in the Kursk sector.

In the Bakhmut sector, the Russian Ministry of Defense announced the capture of Stupochky south of Chasiv Yar, but war blogger Anatoly Radov does not confirm this information ( 1, 2 ), writing that the AFU still has a makeshift transit camp for Ukrainian infantry in the western part of the village, in the house of some “old man with Starlink.” Meanwhile, in the town of Chasiv Yar, Ukraine's 24th Separate Mechanized Brigade repelled a major Russian assault with the use of motorcycles and armored fighting vehicles.

In the Toretsk sector, Russian sources reported the capture of Zoria and Stara Mykolaivka, which entails the elimination of the pocket between Romanivka and Oleksandropil. In addition, the Russian Armed Forces occupied Romanivka proper and advanced to the southern outskirts of Dyliivka north of Toretsk.

Finnish OSINT analyst Emil Kastehelmi of Black Bird Group argues that the Russian offensive between Pokrovsk and Kostiantynivka poses multiple significant threats to Ukrainian defenses. According to Kastehelmi, Russia's operational objectives in this area for the coming months could include:

• creating a threat of encirclement for Kostiantynivka
• creating a threat of encirclement for Pokrovsk
• destabilizing urban Ukrainian supply and command posts in the combat zone

Kastehelmi notes that a dangerous salient between Kostiantynivka and Pokrovsk has already been formed, leaving Kostiantynivka the most vulnerable. Nevertheless, a large-scale breakthrough has yet to occur, and the AFU's top priority is to conduct a competent retreat and maneuver its reserves accordingly.

An investigator writing under the user name Playfra reports on the construction of a new 350-kilometer Donbas defensive line, from Kharkiv to Vilne Pole on the border of the Zaporizhzhia Region. The fundamental difference between this line and previous ones is the deliberate placement of independent fortified positions and firing points designed with consideration of terrain features. The line makes use of natural obstacles such as rivers and hills, and its construction incorporates lessons learned from drone warfare.

Ukrainian OSINT resource Oko Gora ✙ News and Analytics published a map of territorial control changes in the Ukrainian theater of operations from May 19 to May 25. The map indicates that the Russian Armed Forces occupied 188 additional square kilometers, advancing at a daily rate of 27 square kilometers. DeepState estimates this to be Russia's fastest advance of 2025. Russian independent publication Agentstvo attributes the acceleration to a spike in Russian assault operations on several fronts and the cumulative effect of the prolonged offensive.

Mutual strikes and sabotage

The AFU Air Force reported ( 1, 2, 3, 4, 5, 6, 7 ) downing 604 Shahed-type UAVs and drones of other unidentified types out of the 1,231 launched against Ukrainian territory during the week. Another 420 UAVs were radar-lost under the influence of electronic warfare tools. The Ukrainian Air Force also reported intercepting 60 of the 100 missiles launched, of various types. The Russian raid on the night of May 25 set the record for the number of air attack assets recorded: 367, including 298 drones and 69 missiles.

An investigator with the user name Cyrus published ( 1, 2 ) a graph of Shahed interceptions by Ukrainian air defense units. The intercept rate began to decline in mid-March and fell significantly in late April and early May before recently rebounding. The OSINT project In Factum attributes this slump to the emergence of modernized Russian UAVs equipped with more powerful engines and capable of flying at higher altitudes, beyond the reach of mobile air defense systems.

The Russian Ministry of Defense, for its part, reported downing 1,033 Ukrainian fixed-wing drones over the territory of Russia and occupied Crimea. The ministry also reported that Russian air defenses intercepted 2,331 drones between the evening of May 20 and the morning of May 27, with 1,465 of them downed beyond the “special military operation” zone.

According to data collected by CIT volunteers ( 1, 2, 3, 4, 5, 6 ), between 20:00 on May 22 and 20:00 on May 29, shelling of civilian infrastructure on both sides of the front killed at least 57 civilians and injured 335 others.

Losses

The BBC Russian Service and the independent publication Mediazona, jointly with a team of volunteers, have identified 110,608 combatants who died in the war on the Russian side. As follows from their estimates, residents of poorer Russian regions such as Tyva or Altai Krai are 30-40 times more likely to die on the battlefield than Muscovites are.

The independent publication Important Stories studied federal budget execution statistics and estimated that between 374,200 and 407,200 people signed contracts with the Russian Armed Forces in 2024. The pace of enlistment has slowed from the previous year, with an average of 1,700 people a day signing a contract in Q4 2024 — 1.3 times fewer than in the same period of 2023.

Oryx volunteers have now counted more than 4,000 visually confirmed losses of Russian tanks during the war. 2,946 units were destroyed and another 533 captured as trophies. The remainder were either abandoned (392) or merely damaged (158).

Weapons and military vehicles

Europe is discussing pathways to procure weapons from the U.S. on behalf of the Ukrainian Armed Forces in the event that the Trump administration withdraws military aid to Ukraine or exhausts packages agreed to by the previous administration, Bloomberg reports. The Insider previously wrote about Ukraine’s critical dependence on U.S. supplies for certain types of ammunition, particularly surface-to-air missiles for Patriot systems, along with HIMARS rockets.

During the week, the following military aid packages to Ukraine became known:

• The German government will allocate roughly €5 billion to support the AFU in the production of weapons systems (including long-range weapons) and supplies of ammunition and air defense systems.
• Member states of the international “drone coalition” pledged to allocate €2.75 billion in support for Ukraine in 2025. As of the end of May 2025, €180 million has been contributed to the joint UAV procurement fund coordinated by the United Kingdom.
• The Dutch Defense Ministry published footage of the shipment of the last of the 24 F-16 fighter jets promised to Ukraine.
• The Swedish government will allocate 4.8 billion kronor (about €440 million) for contributions to multilateral funds and initiatives to strengthen Ukraine's defense capabilities, including under the Danish model and the Czech initiative.
• Latvia sent 1,500 drones to Ukraine. Defense Minister Andris Spruds pledged that by the end of the first half of 2025, two Latvian companies will deliver 12,000 drones.

As for Russia's partners, this week shed light on several instances of direct or indirect Chinese assistance to Moscow in the war against Ukraine:

• China supplies machine tools, special-purpose chemicals, gunpowder, and other components to Russian military plans, according to Oleh Ivashchenko, head of Ukraine's Foreign Intelligence Service.
• According to Volodymyr Zelensky, Chinese authorities have restricted the sale of Mavic drones to Ukrainian and Western buyers, thus advantaging the Russian side.
• The Insider discovered that China's Jiangsu Feiya Chemical Industry has been supplying Russia with diphenylamine — an essential component of gunpowder — in volumes sufficient to produce half of all the gunpowder consumed by the Russian Armed Forces in 2024.

Russia's drone arsenal has been augmented by jet-powered UAVs converted from Dan-M target drones, which are launched from Mi-8 helicopters. In turn, Russian front-line craftsmen presented the following innovations:

• Anti-FPV drone armor made of tires for artillery barrels
• A BMD-2 airborne infantry fighting vehicle with rubber-and-textile makeshift armor on the turret and metal screens on the sides
• “Hedgehog tanks” with steel bars for protection against UAVs.