Ukraine asked the global chemical weapons watchdog in The Hague on Tuesday to investigate the alleged use of banned toxic munitions by Russia against its forces.
A request to establish an investigation was submitted by Kyiv to the governing body of the organization for the Prohibition of Chemical Weapons (OPCW).
It followed Dutch and German intelligence agencies Friday saying they had evidence of widespread use of illegal weapons by Russia along the frontline.
The OPCW created a similar team in 2018 to examine accusations of chemical weapons use in Syria. The Investigation and Identification Team found that Syrian government forces and Islamic State militants had used banned chemical weapons in the civil war that began in March 2011.
The United States first accused Russia in May last year of using chloropicrin, a chemical compound more toxic than riot control agents and first used by Germany during World War One.
The Organisation for the Prohibition of Chemical Weapons (OPCW), a disarmament agency in The Hague with 193 member states, said last year that initial accusations leveled by both countries at each other were "insufficiently substantiated."
Both sides have denied using chemical weapons in the conflict, which escalated when Russia invaded Ukraine in February 2022.
"Ukraine hereby requests the Director-General of the OPCW to take steps towards establishing an independent and impartial mechanism (to) investigate cases of alleged use of chemical weapons in Ukraine," a copy of the request shared with Reuters said.
It asked that the mechanism be empowered to "collect additional evidence and identify perpetrators, organizers, sponsors of such use."
It was submitted at the beginning of four days of closed-door meetings by the 41-country Executive Council of the OPCW. The disarmament body had no immediate comment on the request.
At least three Ukrainian deaths have been tied to chemical weapons use, the Dutch Military Intelligence Agency said, while more than 2,500 people injured on the battlefield reported chemical weapons-related symptoms to Ukrainian health authorities.
Britain targeted two Russian individuals and one Russian entity Monday as part of its chemical weapons sanctions regime, in its latest effort to punish Moscow for the war in Ukraine.