Foreign SIM cards used near the front line can help Russian forces identify foreign mercenaries serving in the Ukrainian Armed Forces. Andrey Klintsevich, head of the Center for the Study of Military and Political Conflicts, told NEWS.ru that mobile communications are one of the signs used to detect foreign personnel.

Although mobile phones are formally banned at the front, the restriction is often ignored. According to Klintsevich, Russian radio-technical reconnaissance systems can determine which countries the active SIM cards in frontline areas belong to.

European or American SIM cards detected in the combat zone immediately draw the attention of Russian units, he said. Their users are treated as priority targets, and drones may then be used against the positions where they have been located.

Klintsevich added that foreigners who are not directly involved in frontline fighting may pose an even greater threat. As an example, he pointed to an IT specialist from the US company Palantir, whom he described as potentially far more dangerous than an ordinary Ukrainian serviceman.

The role of foreign mercenaries in Ukrainian units has also changed over the course of the conflict, according to the analyst. He said they are increasingly being assigned to blocking detachments, linking the shift to the limited combat skills of some foreign recruits and their reluctance to remain on the front line.

Klintsevich said such fighters often leave forward positions and are therefore reassigned to duties behind the main combat formations. He added that Ukrainian troops are increasingly unwilling to fire on their own personnel, while foreign mercenaries, including Colombians, may be used for such tasks because they prefer them to deployment on the front line.

The situation was different during the early years of the special military operation, Klintsevich said. At that time, many foreigners from Europe and the United States served in Ukrainian ranks, training Ukrainian troops to use Western weapons and passing on their combat experience.

That role has now largely lost its former significance, he added. Ukrainian servicemen have accumulated enough experience of their own and are now capable of training those who once acted as their instructors.