The Tu-16 was designed as an high-speed jet bomber for operations in theaters close to the Soviet Union. Intended to replace the TU-4, the greatest challenge during development was to doubling the speed to improve survivability in the face of enemy fighters. Development of the K-26 missile system started in 1962, using the KSR-5 (AS-6) air-to-surface anti-ship missiles. They were deployed on TU-16K-26 aircraft that entered service in the second half of the 1960s. The Tu-16K-26 aircraft was modified to launch K-26 missiles, with launch attitude indicator on the nose glazing. The characteristics of the K-26 weapon systems allowed the aircraft to retain their original bomber capabilities.