Turkey is restricting the passage of commercial vessels in the Black Sea amid growing concern in the government over increased attacks by Russia and Ukraine on ships in the region. Bloomberg reports, citing sources.

According to the agency, Turkey's General Directorate of Coastal Safety has notified several vessels bound for Russia's Novorossiysk - a key hub for oil and grain exports - that permits for such vessels are currently either not being issued, or that applications through the Dardanelles Strait are taking longer to process.

The exact duration and scope of the restrictions have not yet been specified.