An oil tanker traffic jam formed off the coast of Türkiye after the West’s price cap on Russian crude kicked in and as Ankara demanded proof of full insurance coverage for any vessels navigating its straits, reports said on Monday.

Around 19 crude oil tankers were waiting to cross Turkish waters on Monday, the Financial Times reported, citing ship brokers, oil traders and satellite tracking services.

A $60 per barrel price cap imposed by G-7 nations, Australia and the 27 European Union states on Russian seaborne crude oil took effect this week, the latest Western measure to punish Moscow over its invasion of Ukraine.

The agreement allows Russian oil to be shipped to third-party countries using tankers from G-7 and European Union member states, insurance companies and credit institutions only if the cargo is bought at or below the cap.

Russia said on Monday that a Western price cap on its oil would destabilize global energy markets but would not affect its ability to sustain what it calls its "special military operation" in Ukraine.

According to the Financial Times report, four oil industry executives said Türkiye had demanded new proof of full insurance coverage for any vessels navigating its straits in light of the measures.

The vessels had dropped anchor near the Bosporus and Dardanelles, the two straits linking Russia’s Black Sea ports to international markets.

Vessels have been told they will be unable to travel through the straits without a letter from their insurer, Bloomberg News reported, citing documents.

The first tanker arrived on Nov. 29 and has been waiting ever since, the Financial Times report quoted a ship broker who asked not to be named as saying.