The Varshavyanka-class submarines, also known as the Project 636, are a series of diesel-electric submarines developed by Russia. They are designed for anti-submarine warfare, anti-surface ship operations, and intelligence gathering. These submarines are known for their stealth capabilities, allowing them to operate undetected in various maritime environments. The Varshavyanka-class features advanced sonar systems and can carry a range of weapons, including torpedoes and cruise missiles. They are primarily used by the Russian Navy and have been exported to several countries, enhancing regional naval capabilities and contributing to maritime security.