Ukraine's Defense Forces advanced more than 15 km through underground utility tunnels into Russia's rear on the Kupiansk axis in Kharkiv Oblast, the Khartiia Corps of Ukraine's National Guard reported on 22 October. The corps called it Operation Veles. The underground advance was paired with attacks on the surface and drone strikes, hitting Russian forces from two directions, the corps told Militarnyi.

Russian troops have repeatedly crawled through gas pipelines around Kupiansk to get behind Ukrainian lines, even after Ukraine reported confident control of the city in February. This time, Ukraine went underground itself. The operation took away Russia's chance to get into Kupiansk's rear, the corps said.

The corps reported more than 30 Russian soldiers captured and Russian losses of more than 100. Militarnyi, citing the unit, put the number of Russian troops killed at over 100.

Khartiia studied how Russian troops moved through pipes before going underground itself, the corps commander, Brigadier General Ihor Obolenskyi, said.

"We watched how the enemy works underground and studied how they do it. The Russians intended to use gas pipelines to get into the rear of our troops. So we went underground ourselves. We anticipated the enemy's actions and mastered the tactics of underground combat," he said.

Boots under ground!

Asymmetric breakthrough in the Kharkiv Region: Khartiia Corps conducts the subterranean counteroffensive Operation VELES, advancing 15 km underground.

Corps Commander General Ihor Obolenskyi explains a unique operation. pic.twitter.com/qRQ93kckpK

— Khartiia Corps in English (@khartiia_eng) October 22, 2026

For the operation, troops trained physically and psychologically to fight in confined spaces, sappers and engineers prepared the underground route, and special communications, navigation, silent logistics, and life-support systems were put in place, Khartiia told Militarnyi. The operation was named after Veles, the Slavic pagan god of the underworld.

Khartiia's brigade, the R.U.H. assault regiment, the Lava drone regiment, the Achilles drone brigade, and units of Ukraine's military intelligence, including the Freedom of Russia Legion and the Russian Volunteer Corps, took part, the corps said.

Russia has used pipelines to infiltrate before

By September 2025, Russian forces had used pipelines to move troops behind Ukrainian lines three times, Ukrainian monitoring project DeepState reported on 12 September 2025. The first was in Avdiivka, the second near Sudzha, and the third near Kupiansk, where groups crossed the Oskil River through a gas pipe.

Near Sudzha in March 2025, Russian special forces walked through a pipeline that until recently had carried Russian gas to Europe, the Associated Press reported. A pro-Kremlin blogger claimed they covered about 15 km and that some spent several days inside.

Russian troops kept using the pipeline near Kupiansk this year. On 27 September, Khartiia's reconnaissance drones recorded Russian forces leading nine civilians, including children, elderly people, and a person on crutches, through the gas pipeline out of the Kupiansk community. Men of military age in civilian clothes walked alongside them, and the corps believes they were Russian soldiers using the group as cover to withdraw. Ukrainian troops held fire because of the civilians, the corps said, adding that the case has been documented for a war crimes investigation.

Why the war is moving underground

Drones, constant surveillance, and AI-assisted targeting have made the battlefield surface transparent and deadly, argue John Spencer, chair of urban warfare studies at West Point's Modern War Institute, and Col. Drew Craig, principal military engineering staff officer at NATO's Allied Rapid Reaction Corps. In an August analysis, they write that soldiers in Ukraine describe a "death zone" of some 30 km, where moving above ground can draw an attack within minutes. When firepower makes the surface too dangerous, armies have historically gone underground, as they did in World War I and Vietnam, and more recently in Gaza and Lebanon.

"Armies that cannot survive above ground must adapt below it," the authors write.

Fighting in tunnels brings its own requirements, the authors write: detecting the enemy by sound and vibration, and specialized unmanned systems that cannot rely on GPS or stable radio links. Long stretches underground also take a severe psychological and physical toll on soldiers.

Western militaries are not ready for this, Spencer and Craig write. No NATO partner maintains even general capabilities for large-scale underground warfare, and US and British efforts focused mainly on detecting and clearing tunnels rather than occupying and operating in them.

The suspect allegedly collected relevant information in connection with Russia's war against Ukraine, including on the production of armored vehicles, ammunition, and explosives, as well as on military personnel and facilities on NATO's eastern flank.

Russian forces are preparing to resume mechanized assaults in southern Ukraine after a pause of several months and are moving armored vehicles toward areas where they plan to launch offensives, Anastasiia Shevchenko, deputy spokesperson for the Southern Forces Grouping, told Ukrinform on 22 October. The Huliaipole axis remains the hottest in the Southern grouping’s zone, with 10 to 20 combat engagements reported on an average day, she said.

On the Huliaipole axis, one of Russia’s largest force groupings is fighting Ukrainian forces, comprising units from several Russian combined-arms armies, the spokesperson says. Over the past week, as the weather worsened, Russian forces began local assaults there with infantry, motorcycles, and armored vehicles, seeking to break through toward Zaporizhzhia and blockade the city, Ukraine’s 7th Air Assault Corps reported, adding that the area is one of Russia’s key priorities in southern Ukraine. Russia has used fog this way before: last November, Russian troops moved under its cover to avoid detection by Ukrainian drones as they advanced on Huliaipole, the Institute for the Study of War assessed.

Russian forces have abandoned large-scale assaults across a broad front and are attempting to infiltrate Ukrainian positions in small groups. They periodically use motorcycles and quad bikes for assaults, Shevchenko said, adding that these vehicles are fast and maneuverable.

However, Russian forces should not expect to advance unimpeded, the spokesperson noted. Ukrainian units control Russian supply routes and systematically detect and strike Russian personnel and equipment while they are still moving toward their launch positions, she added.

“Specifically, speaking in numbers, since the beginning of October alone, units of the Southern Forces Grouping (Forces) have destroyed more than 3,000 occupiers and 1,300 pieces of weapons and military equipment. Thus, the enemy is suffering significant losses in the operational zone of the Southern Forces Grouping (Forces),” the spokesperson concluded.

Ukrainian drones disrupt Russian logistics

Russian forces had stopped using military vehicles because Ukraine’s unmanned systems forces controlled their logistics, Shevchenko said in comments to Ukrinform on 16 September. Ukrainian drones spotted Russian troops and equipment in time and struck them mostly on their routes of advance, she said.

Ukrainian air strikes destroyed bridges near Polohy in Zaporizhzhia Oblast, complicating Russian supply operations along the Huliaipole axis, Ukraine’s 7th Air Assault Corps reported on 21 September. Russian forces had used these bridges to move personnel, heavy equipment, and ammunition for their offensive toward Orikhiv. Disruptions to logistics have forced Russian units to rely more on motorcycles, which are more vulnerable to Ukrainian strikes, the corps said.

Russian forces are also expected to use fog and rain as cover for assaults, Mykola Zinko, deputy commander of the unmanned systems battalion of the 5th Assault Brigade, said on 19 October. Russia has brought up reserves, and its heavy equipment will move out under the fog, he said.