The Project 1135 Burevestnik (Storm Petrel) class was a series of frigates built for the Soviet Navy. Commonly known by the NATO reporting name of Krivak the class developed as Krivak-I, Krivak-II (both navy), and Krivak-III (coast guard) sections.
The ships were designed as a successor to the Riga class, started in the late 1950s and maturing as anti-submarine in the 1960s. A total of 40 ships were built, 32 ships for the Soviet Navy (Russian Navy) and 8 modified ships of Nerey (Krivak III) subclass for the KGB Maritime Border Guard. Currently 7 of Nerey subclass are in FSB Coast Guard and one is part of Ukrainian Navy.
The ship's unique features—the bow missile box, the stack and the angled mast, earned it a rap-like nickname among US sailors that comes from their foreign ship silhouette identification training — "Hot dog pack, Smokestack, Guns in Back — Krivak."
How many ships remain in active duty is uncertain. According to some sources Russia has four units in service and the Ukrainian Navy one. Russian press listed three units operational in February 2008, one with the Baltic Fleet and two with the Black Sea Fleet (BSF). With thanks to Wikipedia!