The UK has sanctioned Russian soldiers it says have used chemical weapons on the battlefield in Ukraine.

Russia’s Radiological Chemical and Biological Defence troops, and their commander Lt Gen Igor Kirillov, will be subject to an assets freeze and travel ban. Two of the Russian defence ministry’s scientific laboratories have also been designated.

Kirillov is also a “significant mouthpiece for Kremlin disinformation”, the Foreign Office said.

The US has previously accused Russian forces of using hazardous chemicals in Ukraine, including “riot control agents” such as tear gas and the toxic choking agent chloropicrin – first deployed in battle during World War One.

Foreign Secretary David Lammy said the UK would not sit “idly by whilst Putin and his mafia state ride roughshod over international law, including the Chemical Weapons Convention”.

Lammy called Russia’s “flagrant” use of chemical agents “cruel and inhumane” and vowed to use all the powers at his disposal to combat the “malign activity”.

Announcing the sanctions, defence Secretary John Healey said: “Our message to Putin and his regime is clear: you cannot break international law without facing the consequences.”

Healey said the two Russian Ministry of Defence centres were sanctioned for providing “support for the development and deployment of these inhumane weapons for use on the front lines”.

The UK is providing Ukraine with vital equipment and training to protect its people against chemical weapons, he added.

In May, the US accused Russia of deploying chemical weapons as a “method of warfare” in Ukraine, in violation of international laws banning their use.

State Department officials said Russia used the choking agent chloropicrin to win “battlefield gains” over Ukraine.

The Kremlin rejected the accusations at the time, calling them “baseless”.

The Organisation for the Prohibition of Chemical Weapons (OPCW), a global watchdog that oversees implementation of the CWC, says a chemical weapon is a substance used to cause intentional death or harm through its toxic properties.

Chloropicrin – which the US says Russia has used to “dislodge Ukrainian forces from fortified positions” – is an oily substance which was widely used during World War One. It causes irritation of the lungs, eyes and skin and can cause vomiting, nausea and diarrhoea, according to the US Centre for Disease Control (CDC).

The chemical’s use in war is expressly banned under the CWC, and is listed as a choking agent by the OPCW.

US officials have previously said Russian troops regularly used “riot control agents,” like tear gas, during the war in Ukraine.