Turkish President Tayyip Erdogan called for a ceasefire in the rebel-held region of Idlib in northwest Syria on Friday and said an anticipated government assault on insurgents there could result in a massacre.
But Russia’s President Vladimir Putin said Moscow opposed a truce, and Iranian leader Hassan Rouhani said Syria must regain control over all its territory.
The three presidents, whose countries’ are key foreign players in Syria’s long civil war, were speaking at a summit in Tehran aimed at charting a way to end the conflict.
The situation in Idlib, the insurgent’s only remaining major stronghold, is an immediate issue as President Bashar al-Assad’s forces, backed by Russia and Iran, prepare for what could be the conflict’s last decisive battle.
The United Nations has warned an assault could lead to a humanitarian catastrophe. But as the leaders gathered in Tehran, Russian and government warplanes hit rebel-held parts of Idlib, the Syrian Observatory for Human Rights war monitor said. 
Tehran and Moscow have helped Assad turn the course of the war against an array of opponents ranging from Western-backed rebels to Islamist militants, while Turkey is a leading opposition…