Russia's Black Sea Fleet's 810th Naval Infantry Brigade confirmed that it is deliberately using chemical weapons against Ukrainian forces in an apparent violation of the Chemical Weapons Convention, to which Russia is a party. 

The 810th Naval Infantry Brigade published a long post to its Telegram channel on December 22 detailing a "radical change in tactics" that the brigade is using against Ukrainian forces in Krynky (on the eastern bank of Kherson region).

The post claimed that elements of the 810th Naval Infantry Brigade rotated into the Krynky area and are applying the new tactic of "dropping K-51 grenades from drones" onto Ukrainian positions to smoke Ukrainian forces out of their positions and expose them to fire from various arms.

The 810th Naval Infantry Brigade additionally published footage that apparently shows such a K-51 drop on a Ukrainian position, presumably in Krynky.

K-51 aerosol grenades are filled with irritant CS gas (2-Chlorobenzalmalononitrile), a type of tear gas used for riot control (also known as a Riot Control Agent [RCA]).

The Chemical Weapons Convention (CWC) prohibits the use of RCAs as a method of warfare, and Russia has been a state party to the CWC since 1997.[20] ISW previously observed that Russian forces used K-51 grenades against Ukrainian positions in Donetsk Oblast in November 2022.