Russia has been accused of using chemical weapons in Ukraine as Vladimir Putin is once again faced with war crime allegations.

Moscow’s forces are accused of using chloropicrin to “dislodge Ukrainian forces from fortified positions and achieve tactical gains on the battlefield”, the US State Department said.

Chloropicrin is a toxic substance that was originally designed for use as a poison gas in World War 1.

The State Department added the use of the gas and other “riot control agents” was “not an isolated incident” and came “from the same playbook as [Russia‘s] operations to poison Aleksey Navalny and Sergei and Yulia Skripal with Novichok nerve agents.”

Navalny survived a poisoning attempt back in 2020 before dying in a Russian prison this year.

READ MORE: Vladimir Putin warned he could ‘lose his life’ as Ukraine prepares huge attack

Sergei and Yulia Skripal survived a novichok poisoning in Salisbury, the UK, back in 2018.

The US Treasury Department has imposed new sanctions on Russia in response to the allegations of the use of chemical weapons.

Treasury Secretary Janet Yellen said: “Today’s actions will further disrupt and degrade Russia‘s war efforts by going after its military-industrial base and the evasion networks that help supply it.

“Even as we’re throwing sand in the gears of Russia‘s war machine, President (Joe) Biden’s recently passed National Security Supplemental is providing badly-needed military, economic, and humanitarian support to bolster Ukraine‘s courageous resistance.

“Combined, our support for Ukraine and our relentless targeting of Russia‘s military capacity is giving Ukraine a critical leg-up on the battlefield.”

Russia faces a catalog of war crime allegations.

In the first few months of the war, mass graves were found in Bucha, a city in Ukraine’s Kyiv Oblast. Putin’s forces were accused of killing unarmed civilians as well as torture and rape.

Local authorities said 458 bodies were recovered from the town, including nine children under the age of 18.

Russia is also facing war crimes charges for the deportation of Ukrainian children, forcibly transferring almost 20 thousand Ukrainian children to areas under its control.