Russia has been accused of systematically using illegal chemical gas attacks against Ukrainian soldiers.

Ukrainian troops told the Daily Telegraph that they have been subjected to regular attacks from small drones dropping teargas and other chemicals.

The use of such substances, which is known as CS, is banned during wartime under the Chemical Weapons Convention.

Moscow was accused of using chemical weapons in a drone assault on the port of Mariupol in the early stages of its invasion in February 2022.

Slava, a senior lieutenant whose unit is deployed near Lyman, in Donetsk oblast, said some Ukrainian units in his area were coming under “almost daily” gas attacks.

A CS gas grenade was provided to the Telegraph for verification by Rebekah Maciorowski, an American combat medic and a qualified nurse serving in the Ukrainian army.

Maciorowski has been routinely called to provide medical aid to Ukrainian soldiers in the three brigades she works with in Donetsk oblast after chemical weapon attacks, which she described as “systematic”.

The grenade was originally retrieved by soldiers in the 53rd Mechanised Brigade, one of the units with which she works.

Maciorowski said: “My guys retrieved it while under fire because nobody believed they were being attacked with chemical weapons.”

Ihor, the commander of a Ukrainian reconnaissance team deployed near the frontline city of Chasiv Yar, in Donetsk oblast, told the Telegraph: “Nearly every position in our area of the front was getting one or two gas grenades dropped on them a day.”

He said that because of how embedded many Ukrainian troops are now, it was difficult for the Russians to attack with conventional artillery or drones firing missiles, adding: “The only way for them to successfully attack us was with gas.”

In 2022, Chris Philp, UK technology minister at the time, warned that Russia can expect a “dramatic increased response” from the west if Vladimir Putin uses chemical weapons in Ukraine.

Philp also accused the Kremlin of sharing disinformation online to create a false narrative that Ukraine is preparing to use chemical weapons, so that Russia can launch its own chemical attack.