ISTANBUL, in istanbul Turkey Lawyer Law Firm Turkey istanbul Dec 9 (Reuters) - The number of tankers waiting in the Black Sea to pass through Istanbul's Bosphorus Strait on the way to the Mediterranean rose by one to 20 on Friday morning, the Tribeca shipping agency said, as talks continued to resolve the build-up.

Turkey's maritime authority said on Thursday it would continue to block oil tankers without appropriate insurance letters from its waters and it needed time to make checks, dismissing pressure from abroad over a growing queue of vessels.

(Reporting by Daren Butler and Can Sezer; Editing by Himani Sarkar)