Foreign Minister Sinirlioğlu first had a trilateral coordination meeting on Syria with John Kerry, US Secretary of State and Adel bin Ahmed Al-Jubeir, Foreign Minister of the Kingdom of Saudi Arabia in Vienna, on 23 October 2015.

Foreign Minister Sinirlioğlu later participated, with his US, Russian and Saudi counterparts, in the quartet meeting where Syria issue was raised. In the meeting, possible ways to resolve the crisis in Syria were discussed.