Turkey controls the strait under the Montreux Convention of 1936, which states that in times of war, Turkey can block access to warships belonging to the states bordering the Black Sea, provided they do not not return to their permanent bases there.
Turkish officials, including Çavuşoğlu, said yesterday that Russia’s invasion of Ukraine constituted a war, a change in tone after officials previously described it as a “military operation”, even condemning Russia’s actions.
According to the convention, Black Sea countries must notify Turkey eight days in advance of their warships, including submarines, transiting through the strait while warships belonging to other nations require 15 days notice. Jhe decision to block ships could affect around 16 Russian warships and submarines currently in the Mediterranean, some of which are part of their Black Sea Fleet.
Following a meeting of his cabinet, Turkish President Recep Tayyip Erdoğan said earlier today that “we have decided to exercise the authority granted to our country by the Montreux Convention regarding maritime traffic on the strait in order to ‘prevent the escalation of the crisis’.
Erdogan has repeatedly offered to mediate between Russia and Ukraine, as part of efforts to maintain his alliances with both sides. Turkey imports about a third of its natural gas from Russia and previously bought Russia’s S400 missile defense system, but has recently strengthened economic and defense ties with Ukraine, including by selling Turkish Bayraktar TB2 drones from Kiev.
“Throughout this process, we have uninterruptedly maintained our multifaceted diplomatic initiatives to ensure peace and stability, and we continue to do so,” Erdoğan said.