Russian Foreign Minister Sergey Lavrov called on Turkey to fulfill its responsibilities to end tensions in the rebel-held Syrian province of Idlib today, saying Ankara needed to distinguish between Jabhat al-Nusra terrorists and Syrian rebels. Lavrov’s comments, made during an official visit to Armenia, were seen as a fresh rebuke to Turkey over its reluctance to confront the militant opposition group known as Hayat Tahrir al-Sham, which remains entrenched in Idlib and is led by former members of the al-Qaeda-linked Jabhat al-Nusra.

Turkish President Recep Tayyip Erdogan and his Russian counterpart Vladimir Putin spoke on the phone Sunday to discuss developments in Syria ahead of the Turkish leader’s Nov. 13 meeting in Washington with President Donald Trump.

Erdogan will have likely reassured Putin that he has no intention of succumbing to US pressure to scrap plans to activate the S-400 missile batteries it is in the process of acquiring from Russia. But Lavrov's pinpricks today suggest that Russia will continue to use Idlib as a pressure point to keep Ankara in line.

Turkey maintains 12 military observation posts in Idlib, part of a mission to deconflict Syrian government and opposition forces but more broadly to forestall a full-scale Syrian government attack. Russia wants Ankara to clear the way for the Syrian army’s Russian-backed campaign to retake the province. Turkey fears that such an onslaught would drive hundreds of thousands of more displaced Syrians toward its borders as Erdogan’s government faces mounting public malcontent over the presence of more than 3.7 million Syrians, the highest number of refugees in the world.