The Polnocny classes are the largest series of landing ships in service with any navy. They were designed in Poland, in cooperation with the Soviet Navy and were built in Poland between 1967 and 2002. These ships were in service with the Navies of USSR, Vietnam, Egypt, Algeria, Libya, Yemen, Ethiopia, Cuba, Syria and Bulgaria.

The Polnocny LSM (medium landing ship) series consists of three principal variants, with the design being enlarged and improved during the construction period. The Polnocny-class ships are classified as medium landing ships in the Russian Navy, and are loosely equivalent to Western tank landing ships. They are equipped with a bow ramp that allows beach landings. The Polnocny-A version can carry 9 ZIS-151 military trucks or 19 GAZ-69, or 5 Main Battle Tanks, or 140-180 Infantry Soldiers with their weapons. Unlike their Western counterparts, these ships can provide substantial fire support for landed troops with their onboard multiple rocket launchers. Other armament consists of anti-aircraft guns and short-range surface-to-air missiles.

Medium Landing Ship SDK-32 laid down on 01 March .1965 at the Stocznia Polnocna Shipyard, Gdansk, Poland (yard No.770MA/23), launched on 30 September 1965, commissioned on 31 March 1966 and was assigned to the Black Sea Fleet.

On July 1977 the ship was transferred from USSR to the Southern Yemen Navy, renamed to Sira.