A US-registered NATO patrol plane spent more than seven hours flying over the Black Sea on Friday, an air traffic control service source told TASS. The plane regularly performs surveillance flights over international waters in the southern Black Sea, and spends hours flying back and forth between the western and eastern parts of the region. "The plane was spotted in the area for the first time this week, spending just over seven hours there in total," the source said. He noted that during several passes, the plane flew almost to the Romania-Ukraine border, making repeated loops over the surrounding area.