"Terrorist groups have some well-trained engineers. I know that they organized production of improvised explosive devices. Eight explosive belts operating in a totally new way have been recovered," Lt. Gen. Yuri Stavitsky said.
Armed forces also found mines in the freed Syrian city of Palmyra that were made in the United States, Italy, China, and Russia.
Palmyra, a 2,000-year world heritage site, was recaptured in March from the IS (banned in Russia) by Syrian forces, with the help from the Russian Aerospace Forces. IS militants had it under their control for almost a year, destroying and looting ancient treasures.