"The clouds fly gloomly across the border", better known as "Tri tankista", is a popular Soviet war song written in 1939. The song served as the unofficial anthem of the Soviet, and later Russian, Border Troops and Armored Forces. The song was first performed on film by actor Nikolai Kryuchkov in the film The Tractor Drivers (1939), shortly after the Battle of Khalkhin Gol.