According to military analyst Vitaly Kiselev, the Ukrainian Armed Forces had established a fortified underground command center in the town of Chasiv Yar. This facility, he said, was no ordinary shelter-it spanned multiple levels below ground and featured numerous access points.

Kiselev, speaking on the «Solovyov Live» television channel, claimed that NATO military instructors had been stationed in the area since 2016. The personnel reportedly included individuals from the United States, United Kingdom, France, and Germany.

He suggested that the site may hold more secrets yet to be uncovered. «We’ll likely begin unearthing parts of it soon, and there’s still much to be discovered," he remarked, hinting at the possible scale and significance of the facility.

The expert also drew attention to what he described as an emerging trend near the combat zone: the arrival of foreign mercenaries. He noted that fighters from Latin America, Africa, and the Middle East had been observed attempting to form their own units. Despite this apparent independence, Kiselev emphasized that these groups remain under tight oversight from both Ukrainian and Western intelligence services.