Ukraine accuses Russia of increasingly frequent attacks using banned chemical components, including tear gas.
In May, Kiev recorded 715 cases of Russian ammunition containing "toxic chemical compounds", according to the military. This represents an increase of 271 cases compared to the previous month.
Nearly 1,400 soldiers are reported to have sought medical attention with symptoms of exposure to chemical weapons. According to Ukraine, Russia is equipping grenades released by drones with the banned substances.
Throughout the war, Kiev and Moscow have repeatedly accused each other of war crimes, including chemical warfare. Last month, the US also accused Russian forces of using chemical weapons, primarily the highly toxic chemical warfare agent chloropicrin, in Ukraine.
The use of chemical and tear gas violates the Convention on the Prohibition of Chemical Weapons, which has been ratified by most UN member states – including Russia.