ISIS elements (banned in Russia) and other terrorist groups remain active in Syria's Idlib, U.S. special envoy for Syria James Jeffrey said, noting that it is a major concern for Washington.
The northern Syrian province of Idlib is the last remaining stronghold controlled by terrorists. According to Russia's General Staff, most territory of the Idlib de-escalation zone is controlled by militants from the Jabhat al-Nusra terrorist group (banned in Russia), RIA Novosti reported.
