According to the official, all previous conferences on the Syrian issue stressed the necessity of Syria remaining united, "therefore all attempts to create some autonomous region within Syria get rejected."

"Of course, you followed the visit of de Mistura to Syria and you know of the proposals he made regarding establishment of autonomy for eastern Aleppo. These suggestions were rejected by the Syrian leadership," Haddad told a press conference, Sputnik News reported. 

Syria has been gripped by foreign-backed militancy since March 2011. De Mistura estimates that over 400,000 people have been killed in the conflict.