Ukrainian military authorities loaded the bodies of Russian soldiers collected after fighting in the Kyiv and Chernihiv regions onto refrigerated rail cars on Friday.

Volodymr Lyamzin, the head of Ukraine’s civil-military cooperation, said his country was acting in accordance with international law and was ready to return the bodies to Russia.

"According to the norms of international humanitarian law, and Ukraine is strictly following them, after the active phase of the conflict is over, sides have to return the bodies of the military of another country.

"Ukraine is ready to return the bodies to the aggressor,” he said.

Lyamzin 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 a facility on the outskirts of Kyiv filmed by Reuters.

"In this refrigerator train several hundred bodies of Russian occupiers are kept. Most of them was brought from the Kyiv region, there are some from Chernihiv region, and from some other regions too," Lyamzin said.

Moscow calls its invasion of Ukraine a "special military operation" to demilitarize a neighbour 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.

(Reporting by Sergiy Karazy; Writing by Mark Porter; editing by Grant McCool)