NATO warships entered the Black Sea on Thursday for what the alliance said were long-planned exercises and routine visits to ports in Romania and Bulgaria. The move was not linked to the tensions over Russia's invasion of Georgia, which lies on the eastern shore of the Black Sea, about 900 kilometers from the Romanian coast, said officials at NATO's military command in southern Belgium. Three warships - from Spain, Germany and Poland - sailed into the Black Sea on Thursday. They are due to be joined by a US frigate, the USS Taylor, later this week. However, the move risks increasing tensions with Russia which has deployed ships from its Black Sea fleet to the Georgian coast.