Russian troops are trying to drag Radkivka, a village on the northern edge of Kupiansk in Kharkiv Oblast, into the gray zone so their infiltration groups can keep reaching the city, Viktor Trehubov, spokesperson for Ukraine’s Joint Forces Grouping, said on national television on 27 October, Ukrinform reported. Russian forces made three attempts to advance toward Radkivka on 26 October, Ukraine’s General Staff reported.

Russia has tried for more than a year to retake Kupiansk, a city on the Oskil River, largely by slipping small groups through a disused gas pipeline under the river. They kept using it even after Ukraine said in September 2025 that it had flooded three of the four pipe strings, until Ukrainian troops went into the pipes themselves in Operation Veles, announced on 22 October.

Russian groups now have to move above ground

The pipe Russian groups used to seep toward Kupiansk has been put out of action, so they now have to go through Radkivka or neighboring Holubivka, Trehubov said. They move along the bank of the Oskil and a nearby tree line, but the foliage will soon be gone, which will make that much harder.

When the battlefield became transparent, the war went underground.

Khartiia Corps, together with other Defense Forces units, is conducting the underground Operation VELES, and for the first time, we can show the work of our brothers-in-arms in this new dimension of warfare.

“We… pic.twitter.com/Af3RqgSIr8

— Khartiia Corps in English (@khartiia_eng) October 21, 2026

On the western bank of the Oskil, Russian forces took losses from Ukraine’s Khartiia Corps and in Operation Veles, and their logistics have “suffered noticeably,” Trehubov said. Advancing there is now harder for them than it was a month ago, he added.

Everything now depends on how the fights for Holubivka and Radkivka end, Trehubov said.

“If Ukrainian control can finally be established there, the Russians will have nowhere much to crawl through,” he said.

Several dozen Russian soldiers remain in low-rise buildings in northern Kupiansk, and Ukrainian forces are working to cut off their rotations, Trehubov said on 23 October.

Each side wants the other off its bank of the Oskil

On the eastern bank, Russian forces keep pushing toward the village of Podoly and Kupiansk-Vuzlovyi, a railway junction town southeast of Kupiansk, aiming to wipe out Ukraine’s foothold there, Trehubov said. Ukraine wants to destroy the Russian foothold on the western bank.

“For that, we will need to at least somehow throw them out of Dvorichna,” Trehubov said, referring to a town north of Kupiansk.

The US-based Institute for the Study of War (ISW) assessed that Russian forces conducted no offensive operations on the Kupiansk axis on 26 October, likely because Ukraine now controls the pipeline, a view at odds with the General Staff’s report for that day.

Ukraine reported confident control of Kupiansk as early as February, yet Russian groups kept slipping into the city for months afterward. Trehubov’s latest assessment stops short of declaring that threat over: Russia will still try to advance, he said.

Ukrainian forces have liberated more territory since the beginning of the fall than Russian troops have captured during the same period. This trend has persisted throughout 2026, Ukrainian President Volodymyr Zelenskyy said in his 18 October address. He also reported that Dobropillia, Kostiantynivka, and five other settlements remain under Ukrainian control.

Russia systematically exaggerates its battlefield gains. A recent briefing by Valery Gerasimov, chief of the General Staff of the Russian Armed Forces, in which he claimed that Russian forces had captured 92 settlements since the beginning of September, as well as Kostiantynivka and Dobropillia, and advanced to within 5 kilometers of Zaporizhzhia, was based on “outright lies, manipulation, and exaggerations,” Ukrainian General Staff spokesperson Andrii Kovaliov said.

Ukraine also continues to defend areas near Kramatorsk, Zelenskyy said. He dismissed Russian claims about Zaporizhzhia.

“We are destroying Russians 20 kilometers from Zaporizhzhia, not five, as someone in Russia is fantasizing to Putin,” Zelenskyy said.

Ukrainian forces continue to hold back Russian assaults and destroy groups of occupying troops attempting to infiltrate Dobropillia, the president said. The Defense Forces are also defending positions elsewhere in Donetsk Oblast and in Kharkiv and Zaporizhzhia oblasts.

Zaporizhzhia axis: Russians seek to move artillery closer to the city

Russia seeks to advance on the Zaporizhzhia axis to bring the regional capital within range of its tube artillery, hold forward positions, and protect rear areas from Ukrainian strikes, the Institute for the Study of War (ISW) said on 18 October.

Maksym Kravchuk, spokesperson for Ukraine's Southern Group of Forces, refuted Gerasimov’s claims that Russian forces had captured Malokaterynivka, located south of Zaporizhzhia, stressing that the settlement remains under Ukrainian control, the Center for Countering Disinformation said on 18 October. Ukrainian troops recorded a video directly from Malokaterynivka to confirm this.

As of 18 October, Russian forces had advanced or infiltrated to within 24 kilometers of Zaporizhzhia, ISW said.

Dobropillia remains under Ukrainian control despite Russian assaults

Dobropillia is now a fortress anchoring Ukrainian positions along the highway leading northeast toward Kramatorsk. Russia first tried to take Dobropillia in August 2025 and is now trying again.

Russia is redeploying reinforcements to the Dobropillia axis and continues to send assault infantry through the village of Nove Shakhove despite heavy losses. Russian command will likely try to encircle or at least envelop Dobropillia and cut off Ukrainian supply routes from the direction of Bilozerske, Ukrainian military analyst Kostiantyn Mashovets wrote on 9 October.

Mashovets sees the push as the southern flank of a Russian effort to envelop the whole Sloviansk–Kramatorsk urban area.

Dobropillia remains under Ukrainian control, Zelenskyy said. On 18 October, footage located by analysts showed a Russian soldier hoisting a flag in the town's southeast after an infiltration, yet ISW has found no sign that Russian troops have dug in there.

Russia claimed to have captured Kostiantynivka, but ISW found no evidence

Ukrainian troops in and around Kostiantynivka are stopping Russia from locking in its gains in the city or pushing on toward Druzhkivka and Kramatorsk, ISW said on 17 October.

Russian officials claimed that capturing Kostiantynivka was an important step toward establishing control over the Sloviansk–Druzhkivka–Kramatorsk urban agglomeration and the entire Donetsk Oblast, ISW said in August. The Kremlin also claimed that Russian forces had captured the city as early as 5 July, the institute added.

A Russian military blogger claimed that Russian forces had full control over Kostiantynivka, but ISW found no evidence to support this claim, the institute said in its 16 October assessment. Russian troops had only infiltrated parts of southern and central Kostiantynivka without consolidating positions, and there was no evidence of their presence in its northern part, ISW added.