Daesh fighters' usage of chemical weapons will rise to large-scale and trans-boundary level, the Pravda.Ru cited official representative of the Russian Foreign Ministry Maria Zakharova as saying Thursday.

The Daesh is known to have obtained access to scientific technical documents on the production of chemical weapons. They also seized chemical enterprises and engage foreign specialists in the synthesis development of the chemical warfare agents.

According to Zakharova, there is a threat of the extension of their terror activity beyond the territories of Syria and Iraq, as well as the whole Middle Eastern region.