Ukrainian military officials have previously said that Russia is deploying chemical weapons on the battlefield in violation of the 1925 Geneva Protocol. The usage of riot control gas in war is also banned under the 1997 Chemical Weapons Convention, which Russia is a signatory of. Pakhmov told Reuters that Ukraine had recorded at least 900 uses of the banned riot control gas by Russian forces in the last six months, out of a total of 1,400 times since the beginning of the full-scale invasion. The command of Ukraine's Support Forces said earlier in April that Russia's usage of prohibited chemical weapons has reached "systemic" levels.