Presumably, Muhannad Dhouqan Abu Ammar had been killed by the terrorists, according to images circulated by Daesh, news outlets report.
At the same time, the Syrian Observatory for Human Rights said that more than 30 people had been kidnapped during the July 25 offensive.
Syria has been engulfed in a civil war since 2011, with government forces fighting numerous opposition factions and terrorist groups. The international community has taken a number of steps aimed at settling the crisis, including through negotiations in Geneva and Astana, as well as the Syrian National Dialogue Congress which took place in the Russian city of Sochi in January.
*Daesh (also known as ISIS/ISIL/IS) is a terrorist group banned in Russia