In Severodvinsk, the multi-purpose nuclear submarine K-328 "Leopard" of Project 971M began sea trials after completing deep modernization at the "Sevmash" production association. The ship underwent an upgrade as part of a program to extend its service life and enhance its combat capabilities.

The work included re-equipping the submarine with modern weapon and control systems. The main element of the upgrade was the "Kalibr-PL" missile system, which expanded the submarine's strike capabilities against surface and coastal targets. Radio-electronic systems, navigation equipment, and elements of the sonar complex were also updated.

After the completion of the slipway stage of modernization, the submarine was taken to sea, where testing of its running characteristics, power plant operation, and new control systems began. The trials will be the final stage before the ship returns to the combat-ready forces of the fleet.

The "Leopard" belongs to the series of multi-purpose nuclear submarines of Project 971 "Shchuka-B", which are being upgraded to the 971M level. This class of submarines was created as highly maneuverable hunters for underwater and surface targets with increased stealth and long autonomous cruising range.