Ukraine accused Russia on Friday of using toxic chemicals in more than 200 attacks on the battlefield in January alone, a sharp increase in what it said were recorded instances of their use by Russian forces since they invaded two years ago.

Russia has denied allegations of using chemical weapons in Ukraine and has accused Ukrainian forces of their use, which Kyiv denies.

Neither side has produced evidence and Reuters has not been able to verify any use by either side.

Ukraine has previously accused Moscow of using chloropicrin, which was used as a poison gas in World War I.

The latest statement by Ukraine’s General Staff singled out CS, or tear gas, which it said Russia had used in various grenades.

CS gas, widely used by police forces, is banned on the battlefield by the International Chemical Weapons Convention, opens new tab, which states in Article 1: “Each State Party undertakes not to use riot control agents as a method of warfare.”

The Ukrainian general staff said: “815 cases of the use of ammunition loaded with toxic chemicals by the Russian Federation were recorded. Of these, only in January 2024 – 229 cases.”

It did not name any other chemicals in its statement on the Telegram messenger app.

General Oleksandr Tarnavskyi, commander of the “Tavria” operational grouping based in the southeast, said separately on Telegram that enemy troops deliver chemical-loaded ammunition with drones.

He mentioned chloropicrin chemicals he said had been used on Thursday.

A year ago, Russia accused Ukrainian forces of using unspecified chemical weapons in drones in Russian-occupied eastern Ukraine.