TALLINN (Reuters) -Russia detained a Greek-owned oil tanker on Sunday after it left an Estonian Baltic Sea port, the Estonian Foreign Ministry said, adding it had alerted NATO allies to the incident. The Liberia-flagged ship Green Admire was leaving Sillamae port using a designated navigation channel that crosses Russian territorial waters, the ministry said in a statement. "This is definitely connected to the fact that we have started to harass Russia's shadow fleet", Foreign Minister Margus Tsahkna told Estonian broadcaster ERR.