Iran’s Foreign Minister Mohammad Javad Zarif is due to hold talks with his Turkish counterpart Mevlut Cavusoglu in Ankara tomorrow after meeting with Syrian President Bashar al-Assad in Damascus, Turkey’s state-run Anadolu news agency reported today.

Syria will undoubtedly top the agenda in Zarif’s meetings in Ankara, where the Iranian diplomat’s trajectory will likely excite speculation that he may be carrying messages from Damascus. Assad and Turkey’s President Recep Tayyip Erdogan, who together oversaw an unprecedented boom in bilateral ties, fell out with the outbreak of Syria’s civil conflict in 2011. The break was prompted by Turkey’s support for opposition rebels seeking Assad’s ouster that evaporated following Russia’s decisive intervention in favor of the regime.

But a thaw remains unlikely as long as the United States continues to dangle the hope of a safe zone in the northeastern stretch of Syria under Ankara's military protection. The Donald Trump administration’s Syria envoy, Jim Jeffrey, told an audience of Turkish-American business people yesterday that the proposed haven would be empty of the US coalition’s Syrian Kurdish partners, whom Turkey labels terrorists. The administration views Turkish support as key to curbing Iranian influence in Syria, one reason it is now reportedly leaning toward allowing a limited number of Turkish forces into the safe zone over Kurdish objections.

Russia, which is trying to woo Ankara to its side, has suggested that Turkey’s security concerns can be addressed via the 1998 Adana agreement between Ankara and Damascus. The accord, signed after Turkey threatened to go to war over Syria’s harboring of the now imprisoned Kurdish rebel leader Abduallah Ocalan, allows Turkey to pursue hostile forces inside Syrian territory. The difference is that the Russians do not want Turkish troops to expand their presence inside Syria any further, saying its own military police together with regime forces will assure border security instead.