Their spies, he says, range from low-ranking soldiers to high-ranking officers.

He remembers being shocked to learn there were no children of high-ranking parents in his frontline unit: "That's when I realised we were expendable."

He said the casualties included high-ranking officials, and could be explained by the troops lack of familiarity with the terrain, and with drone warfare.

Kirillov, 54, was the highest-ranking Russian military figure to die outside the battlefield since the start of Russia’s full-scale invasion of Ukraine nearly three years ago.

A high-ranking general in the Russian armed forces and his assistant have been killed in an explosion in Moscow.