Turkish President Recep Tayyip Erdogan is accusing the Syrian government of seeking to “sabotage” Turkey’s relations with Russia with its assault on rebel-held Idlib. In a late-night phone call with Russian President Vladimir Putin on Monday, Erdogan said Syrian President Bashar al-Assad’s attack on the de-escalation zone guaranteed by Moscow and Ankara had reached an “alarming dimension” that cannot be justified with claims of fighting terrorism. With civilian targets, including hospitals, being hit, joint efforts to end the eight-year-long conflict are at risk.

Why it matters: Erdogan’s comments could be interpreted as a signal that the 2018 deal under which Turkey pledged to disarm and edge out Hayat Tahrir-al Sham, an al-Qaeda breakaway group, from areas around Idlib is falling apart. 

Russia agreed in exchange to prevent the regime from mounting a full-scale assault on the province that is now home to 3 million civilians. The UN has warned that any such offensive would trigger a major humanitarian disaster and send an ocean of refugees, with jihadis among them, toward Turkey.

The onslaught began April 28 and has already displaced 150,000 people. Opposition forces say at least 169 civilians have died so far in a campaign preceded by days of intense Russian and Syrian regime airstrikes on northern Hama and southern Idlib.