The T-80 is a main battle tank which was designed in Soviet Union and entered service in 1976. A development of the T-64, it was the first production tank in the world to be equipped with a gas turbine engine for main propulsion (the Stridsvagn 103 used a supplementary gas turbine by 1971). An advanced derivative, the T-84, continues to be produced in Ukraine. The T-80 and its variants are in service in Belarus, Cyprus, Kazakhstan, Pakistan, Russia, South Korea, and Ukraine. The T-80U and T-80UM modifications are currently in production at Omsk, Russia. The chief designer of the T-80 was Russian engineer, Nikolay Popov.