Still, the government on Tuesday vowed it will keep up its campaign against "terrorism," either militarily or with reconciliation deals.
Syria's armed opposition said the Idlib arrangement is a victory for its resistance and will improve its standing after crushing military defeats in recent months elsewhere in the country.
Idlib is home to three million residents and around 60,000 fighters, including some of the world's most radical. Some estimates put the number of radical fighters at about 10,000 who are in control of nearly 70 per cent of the
enclave. The deal aims to end their presence in Idlib.
Some of the militants called supporters of the deal "traitors," warning that it is likely to end with indiscriminate violence.
Such divergent views presaged the challenges that lie ahead in implementing the first-of-its-kind deal. Already, details coming out of Damascus and Ankara appeared to differ, raising concerns about how it would be implemented.
On Monday, Russian President Vladimir Putin said the demilitarized zone is to be established by October 15 and be 15-20 kilometres deep to separate Syrian forces and the rebels, with radical groups withdrawn from the area.
The zone will have troops from Russia and NATO-member Turkey conducting coordinated patrols to monitor the demilitarisation and restore traffic to the highway linking major Syrian cities that passes through Idlib.
The opposition fighters are to give up their heavy weapons, mortars and tanks by October 10, Putin said.
Idlib is the last rebel-held corner of Syria, although foreign troops and local proxies remain in areas adjacent to Idlib and the country's east.
The Syrian Foreign Ministry said the agreement came after consultation between Damascus and Moscow, which has backed Syrian President Bashar Assad since 2015, turning the tide of the civil war his forces were struggling to win.
It said the agreement reached in Sochi, Russia, is bound by a timetable that must be respected, calling it a continuation of previous de-escalation zones.
Russia, Turkey and Iran have declared four de-escalation zones around Syria since last year, all of them but Idlib ended in a military offensive and deals in which the rebels surrendered. Those who refused to accept government
Russian President Vladimir Putin, (L) and Turkish President Recep Tayyip Erdogan prepare to enter a hall for their talks in the Bocharov Ruchei residence Source: AAP
authority were bussed to Idlib, whose population has doubled.
Turkey's Foreign Minister Mevlut Cavusoglu said on Tuesday the arrangement ensures the continuity of Syria's moderate opposition.
He said it would allow civilians and Turkey-backed anti-government rebels to remain in the
demilitarised zone and "retain light arms".
Without the agreement, "there would have been no opposition left," Cavusoglu said, calling it crucial for a lasting political solution.
