Lyamzin told Reuters law enforcement services have been taking biological samples from the bodies and that Interpol experts were among those doing work on the refrigerated trains.
He also said there were several refrigerator trains stationed in different regions across Ukraine where the bodies of Russian soldiers were being kept.
Several hundred bodies were being stored at the facility filmed by Reuters.
Moscow calls its invasion of Ukraine a "special military operation" to demilitarize a neighbor threatening its security. Ukraine denies posing a threat and says Russia is waging a war of aggression that has killed thousands of civilians, uprooted millions of others and destroyed cities and towns since the conflict began in late February.