The Tupolev TB-3 (Russian: Тяжёлый Бомбардировщик, Tyazhyolyy Bombardirovshchik, Heavy Bomber, civilian designation ANT-6) was a monoplane heavy bomber deployed by the Soviet Air Force in the 1930s and used during the early years of World War II. It was the world's first cantilever wing four-engine heavy bomber. Despite obsolescence and being officially withdrawn from service in 1939, the TB-3 performed bomber and transport duties throughout much of World War II. The TB-3 also saw combat as a Zveno project fighter mothership and as a light tank transport.