Russian infantry are attempting to infiltrate Ukrainian lines by crawling through disused Soviet‑era gas pipelines beneath the Oskil River in Kharkiv Oblast. the 15‑kilometre, 1.2‑metre‑wide tunnels give them a brief chance to emerge behind Ukrainian positions, but most soldiers survive only minutes after surfacing, according to the Kyiv Independent.

15‑kilometre crawl through 1.2‑metre‑wide Soviet pipelines

Ukrainian sergeant Andriy Tovsty of the Khartiia Brigade described the route as a "brutal funnel of attrition". Soldiers must crawl roughly 15 km through narrow tnunels that were once part of a gas network linking Kharkiv to Russia. The pipes are barely passable, and drones constantly monitor the surface, making any exposed movement near‑suicidal.

Survival window shrinks to ten minutes after emergence

Ukrainian officials told the Kyiv Independent that a Russian combatant can hope to survive up to an hour after exiting a pipe, but the typical survival time is about ten minutes before Ukrainian fire kills them.. Drone footage repeatedly shows troops popping up from the tunnels only to be engaged instantly.

Kupiansk becomes the focal point of the pipeline gambit

The ultimate objective of the underground trek is the strategic town of Kupiansk , which changed hands early in the 2022 invasion and has been a focal point of Russian attempts to retake the area.. In September 2025, Russian units briefly reached Kupiansk’s northern outskirts via the pipeline network before Ukrainian forces pushed them back, a development later highlighted by President Volodymyr Zelensky’s December visit.

Ukrainian counter‑measures turn the tunnels into a whack‑a‑mole battlefield

Ukrainian commanders describe a months‑long “whack‑a‑mole” struggle: identifying pipe exit points, sealing them, and then confronting new openings elsewhere.. Improved mapping and sealing of sections have reportedly reduced successful infiltrations, though the tactic persists despite heavy losses.

Human cost inside the pipes: suffocation, suicide, panic

Open‑source analysts and Russian media outlet Astra have released soldier testimonies describing appalling conditions: dozens suffocated, some committed suicide, and others panicked to the point of self‑harm. One soldier reported that comrades “went crazy”, with one shooting himself and another smashing his head against the tunnel wall.