"I came to a clear belief during the visit that if Assad is overthrown, public order, security and sovereignty will cease to exist throughout the country," Sener said.
The envoy noted during his trip that vital infrastructure, security and public institutions operate fault-free in Syria's government-controlled regions.
"I am convinced that if Assad is overthrown, various groups with no political traditions, ethical standards,… a clearly defined program and – even worse – that have no idea how to govern, will destroy and raze to the ground everything around them," Sener said.
"The Free Syrian Army [FSA] exists in name only. From time to time, its members enter into clashes with government troops, joining Islamic State militants, the Nusra Front and other terrorist groups," Sener told Sputnik.
Syrian reconciliation talks were held under Russian mediation for the first time since January 2014, when UN-backed negotiations in Geneva, Switzerland failed to provide significant results.
Syria has been in a state of civil war since 2011, with government forces fighting armed rebel groups, including the FSA, and opposition troops.
The Islamic State and Nusra Front militant groups are also involved in fierce clashes with the Syrian armed forces. The former, notorious for brutal tactics and extremist beliefs, has gained up to one-third of Syria's northeastern territories in the wake of the conflict.
The UN estimates more than 200,000 have died in the ongoing violence.
