FILE PHOTO: The logo of the Organisation for the Prohibition of Chemical Weapons (OPCW) is seen during a special session in the Hague, Netherlands June 26, 2018. REUTERS/Yves Herman/File Photo
AMSTERDAM (Reuters) - The world's chemical weapons watchdog on Friday said it had once again found traces of tear gas on the frontline with Russia in Ukraine's central-east Dnipropetrovsk region.
The use of riot control agents such as tear gas as a method of warfare is prohibited under the Chemical Weapons Convention, the non-proliferation treaty overseen by the Organisation for the Prohibition of Chemical Weapons (OPCW).
Ukraine had requested the assistance of the agency, which deployed a team. The team was not mandated to assign blame, but Ukraine and the United States have said Russia has illegally deployed tear gas to clear trenches.
Tear gas is not lethal, but causes temporary irritation to the eyes and respiratory system.
The OPCW said it had retrieved evidence related to three incidents in the region in October and had found traces of tear gas on the grenade shells and soil samples collected there.
In November it had also reported finding traces of tear gas in the region.
(Reporting by Bart Meijer; Editing by Bill Berkrot)