Turkey-Russian ties extend beyond Syria but Idlib is where they are bargaining and strengthening their negotiating hand.
In northwestern Syria, rebels have launched a counterattack against pro-government forces.
Fighting has been intensifying in Idlib and Hama provinces since last month despite a Turkish and Russian-brokered ceasefire.
At least 200 civilians have been killed.
Al Jazeera’s Zeina Khodr reports.