Kirillov was responsible for providing Russian forces with the chemical agents the use against entrenched Ukrainian positions.

Ukraine claims that Russia has used chemical agents 4800 times since the war started.

Since 2022, more than 2,000 Ukrainian soldiers have been hospitalized with chemical poisoning, and 3 have died.

"Russian forces mostly use ammunition with toxic substances by dropping them from FPV (first-person-view) drones on Ukrainian positions. When chemical grenades are detonated, their poisonous compounds affect human mucous membranes, especially the eyes and respiratory tract," the SBU’s statement said.

When detonated, the irritating gases force Ukrainian soldiers finding cover in the trenches to leave and expose themselves to Russian gunfire, the statement noted.

Ukraine handed over soil samples that prove the use of banned materials to independent laboratories of the International Organization for the Prohibition of Chemical Weapons for examination and were confirmed to breach international humanitarian law.

Ukrainian soldiers say the tactic is effective, allowing Moscow to capture positions occasionally without destroying them.

The U.K. issued sanctions against Kirillov and his unit over the use of chemical weapons on the battlefield in Ukraine on Oct. 8.