The shipyard’s authorities declined to comment the reason for the submarine’s return.
Significantly, Krasnodar called at Kronshtadt heading from the Baltic Sea on Monday, May 2. The cruise was assisted by harbor tugs RB-250 and RB-27 registered in the Leningrad Naval Base. The sea-going tug Viktor Konetsky returned to Kronshtadt along with the submarine. According to media reports, the ship was observed near Latvian territorial waters on April 30. Viktor Konetsky accompanied a Kilo-class submarine; Russia’s newest Project 636.3 diesel subs like Krasnodar are often referred to that class, too (on NATO classification – Improved Kilo).
Earlier on, there were reports in the Russian press about a collision between the Russian submarine Krasnodar and the Polish one named Orzeł. Military spokesmen of the both countries rebutted that information; however, the Russian Navy officials specified that a "navigation incident" did happen though.