A drone that entered Bulgaria on Saturday exploded near the Romanian border, about one kilometer from the Trans-Balkan gas pipeline linking Turkey to Ukraine, Bulgarian Prime Minister Rumen Radev announced. Radev did not specify where the drone came from and said authorities had yet to determine its type. “I hope we will soon discover what type it is,” Radev added, describing it as a “larger drone” rather than a “hobby drone.” Bulgaria, Romania and Turkey border the Black Sea, where both Ukraine and Russia have conducted drone attacks. Turkish officials said Tuesday that a drone attack the previous day on two civilian vessels in the Black Sea had injured crew members.