"This intractability could cost the US dearly since terrorism does not boil down to belligerent thugs; it is a parasitic ideology that will find its supporters if its opponents are not united," he said.
In Zavari's opinion, Aleppo is of primary importance to all key stakeholders involved in the Syrian conflict due to its prime geostrategic location.
"Aleppo serves as a link between northern, northwestern and northeastern regions of the country on the one hand and central Syria on the other," he said. "In addition, the city's close proximity to Turkey has long guaranteed its status as the economic capital of the country. This has not been lost on terrorists who diverted a large part of their budget and human resources to secure control over Aleppo."
Zavari also outlined three scenarios with regard to what could happen to extremism in Syria unless the US joins its forces with Russia and Damascus in eradicating terrorist groups trying to overthrow Assad.
"In this case, a coalition of terrorist groups could appear that will pose a real, I would even say, physical threat to the West and the Shia," he said.
The second scenario will see existing terrorist forces morph into "extremist streams that will retain their destructive power." Zavari's third scenario mimics Afghanistan's experience in the sense that terrorist groups will be weakened for some time, but will later recover.