Dutch and German intelligence agencies say Russia has stepped up its use of banned chemical weapons in Ukraine, including the choking agent chloropicrin, in violation of international law.

Evidence suggests thousands of instances of use, with chemicals dropped by drones to flush soldiers from trenches. Russia denies the allegations.

Dutch Defence Minister Ruben Brekelmans called the practice “horrible and unacceptable” and urged tougher sanctions.

Germany’s BND confirmed Russia’s use of tear gas and chloropicrin, which is banned under the Chemical Weapons Convention, Al-Jazeera has reported.

At least three Ukrainian deaths and over 2,500 cases of symptoms have been linked to such attacks.

Written by B.C. Begley