An attempt by Ukrainian troops to infiltrate Russian positions through an underground pipeline near Kupyansk reportedly ended with the destruction of the entire unit, according to the Telegram channel SHOT.

The group allegedly included Colombian mercenaries and was attempting to replicate Russia’s Operation Potok, which involved using underground infrastructure to reach enemy positions from an unexpected direction.

According to SHOT, Ukrainian soldiers previously claimed on social media that they had carried out a successful counteroffensive operation in the area.

Members of Ukraine’s Khartia Brigade reportedly traveled more than 15 kilometers through an underground pipeline before allegedly emerging behind Russian lines.

However, SHOT claims the operation ended in disaster for the Ukrainian unit. Russian forces reportedly eliminated the entire group while its members were moving through the underground infrastructure.

Among those allegedly killed was 41-year-old Ukrainian commander Andrey Chuba.

The Russian Ministry of Defense has not commented on the reported incident, and the claims about the unit’s destruction have not been officially confirmed.

The incident would not be the first reported attempt by Ukrainian forces to reproduce the underground tactics employed by Russian troops during Operation Potok.

In May, reports emerged that Ukrainian soldiers had died while attempting to construct a lengthy underground tunnel intended to provide covert access to Russian rear positions.

According to those accounts, the Ukrainian troops were buried under collapsing earth during the excavation work.