The recent escalation of violence between Turkey and the Assad regime in violation of the Sochi deal marks a significantly tense moment that may risk a deterioration of relations between Ankara and Moscow. Turkey has given an ultimatum to the Assad regime to withdraw its troops outside of the zone encircled by Turkey's military observation points until the end of February. So far, the Assad regime has resisted the idea of withdrawal and continued to expand further into the territory. However, Turkey expects its Russian counterparts to either convince or force the Assad regime to comply with the conditions laid out as part of the Sochi deal that was signed in September 2018. The Sochi agreement proposed the establishment of a demilitarized zone in northwestern Syria in order to protect the country's civilians against attacks by the Assad regime. Radical militant groups such as Hayat Tahrir al-Sham (HTS) were expected to leave Idlib, according to the agreement, while Turkey forwarded the establishment of 15 military observation points to monitor the cease-fire within the boundaries of the Sochi line. Furthermore, the demilitarized zone was to be monitored by mobile patrol groups of Turkish units and units of the Russian military police. Turkey, Russia and Iran were to be mutual guarantors of the agreement. However, the conditions of the deal were never fully implemented on the ground. The lack of a political process and the ongoing conflict further complicates Turkey’s efforts to deal with the radical groups in and around Idlib. The Turkish side expected the Sochi agreement to ease the pressure of accommodating even more refugees and to pave the way for a political process that would lead to a permanent political solution to end the ongoing civil war in Syria. Thus, the Sochi agreement was very well received in Turkey when it was first signed. The agreement was expected to stem the refugee flow to Turkey and Europe. The refugee flow to Turkey was reduced drastically, which allowed Turkey to set up humanitarian safe zones on the Syrian side of the border. Many Syrian civilians from other parts of the country came to the Idlib region after the formation of the demilitarized zone. However, similarly, Idlib became identified as a safe haven for the anti-regime and opposition groups with the signing of the deal. Turkey is already overwhelmed by the presence of close to 4 million Syrian refugees inside its borders. The presence of Syrian refugees is generating significant economic, political and cultural problems for Turkey, especially in the border cities and certain districts of Istanbul and Ankara, where the Syrian refugee populations are mainly concentrated. Pressure and criticism from opposition parties and certain political actors in Turkey on President Recep Tayyip Erdoğan and his party have affected the popularity of the Justice and Development Party (AK Party), as well. Despite those criticisms, President Erdoğan has struggled to maintain Turkey's open-door policy and welcoming approach to the civilian victims of the conflict on humanitarian grounds. The failure of the Sochi deal and further refugee pressure will also undermine the credibility of President Erdoğan in domestic issues, putting him in a more difficult position against European actors. Erdoğan has already mentioned this to his European counterparts, saying that Turkey would accept no more Syrian refugees and that they should go elsewhere. Developments since the summer of 2019 have led to the rise of significant doubts around the Sochi deal. The Syrian regime, with the support of Russian air force and military coordinators, as well as Iranian-backed militias, has intensified its attack on the demilitarized zoned and struggled to take control of key strategic towns around Idlib. The regime side wanted to depopulate the residential areas and push the civilians either close to the border with Turkey or into the Euphrates Shield area. Civilians and civilian infrastructure such as schools, hospitals, market places and critical buildings are deliberately targeted by the regime to push civilians out of the Idlib area. Those attacks also undermine the possibility of a political solution to the Syrian civil war. The violation of the Sochi agreement and a renewed attack on civilians have generated a severe trust issue between the Turkish and Russian sides. Turkey started its military deployment within the Sochi lines to enforce the agreement and help the moderate opposing militias – the Syrian National Army (SNA) – to take back the control of the areas that were controlled in violation of the Sochi deal. Both sides have blamed each other for breaking the deal with differing accusations, but what is clear on the ground is that the Turkish-Russian relations may be deeply damaged due to the uncontrolled military exchange in the field. Top leaders from both sides are considered guarantors in the relationships between Turkey and Russia, but they may be dragged into an unexpected escalation. The Russian military, as well as the country's diplomats, have applied pressure on Turkey to try to impose a new agreement. Still, Ankara will insist on maintaining the de-escalation zone to keep Syrian civilians within the borders of Syria. Systematic violations of the Sochi deal by the Assad regime and Russia have put Turkey in an awkward position. There is increasing skepticism in Turkey about the risks of strategic cooperation with Moscow. Despite President Vladimir Putin's constructive approach in his relations with President Erdoğan, Moscow's diplomatic trustworthiness is now in question in Ankara. So far, the two leaders managed to sort out their differences constructively and, despite the tensions in the field, they are more likely to reach a deal in the recent crisis as well. If the Assad regime and Russia insist on a military approach for the solution to the Syria crisis, Ankara and Moscow are more likely to drift apart on other issues as well.