Turkey has announced that from 1 December oil carriers passing through its straits will have to prove that they are insured.
While this is aimed at maritime safety along its straits, it will also affect the flow of millions of barrels of Russian crude oil exported by sea, as the EU and UK embargo on Russian oil shipments is due to come into force on 5 December, banning shipping services including insurance.
This could limit the flow of Russian oil. Russia was estimated to have transported about 10% of its oil exports through the Turkish straits.