The number of oil tankers waiting in the Black Sea to pass through Istanbul's Bosphorus Strait on the way to the Mediterranean rose to 20 on Friday, Tribeca shipping agency said, as Turkey held talks to resolve an insurance dispute behind the build-up, according to Reuters.
Dismissing pressure from abroad over the lengthening queue, Turkey's maritime authority said on Thursday it would continue to block oil tankers that lacked the appropriate insurance letters, and it needed time for checks.
The ship backlog is creating growing unease in oil and tanker markets and comes as the G7 and European Union introduce a price cap on Russian oil. Millions of barrels of oil per day move south from Russian ports through Turkey's Bosphorus and Dardanelles straits into the Mediterranean.
The maritime authority said that in the event of an accident involving a vessel in breach of sanctions it was possible the damage would not be covered by an international oil-spill fund.
The vast majority of vessels waiting near the straits were EU vessels, with a large part of the oil destined for EU ports - a factor frustrating Ankara's Western allies.
The G7 group of nations, the EU and Australia have agreed to bar providers of shipping services, such as insurers, from helping to export Russian oil unless it is sold at an enforced low price, or cap. However, Turkey has had a separate measure in force since the start of the month requiring vessels to provide proof of insurance covering the duration of their transit through the Bosphorus strait, or when calling at Turkish ports.
Eight tankers were also waiting for passage through the Dardanelles strait into the Mediterranean, down from nine a day earlier, Tribeca said, making a total of 28 tankers waiting for southbound passage. Most of the tankers waiting at the Bosphorus are carrying Kazakh oil and Treasury Secretary Janet Yellen said on Thursday the U.S. administration saw no reason that such shipments should be subjected to new procedures.
Washington had no reason to believe Russia was involved in Turkey's decision to block ship transits, she added. Turkey has had to balance its good relations with both Russia and Ukraine. It played a key role in a United Nations-backed deal reached in July to free up grain exports from Ukrainian Black Sea ports.
Turkey's maritime authority said that it was unacceptable to pressure Turkey over what it said were "routine" insurance checks and that it could remove tankers without proper documentation from its waters or require them to furnish new P&I ship insurance letters covering their journeys.