In mid-November, there were reports of the same submarine allegedly striking targets in the Islamic State stronghold of Raqqa.
The reports were neither denied nor confirmed by the Russian MoD. Russia struck Islamic State (IS, formerly ISIS/ISIL) targets in Syria with modern Kalibr cruise missiles fired from its warships in the Caspian Sea in early October.
Known as ‘Improved Kilo’ under a NATO code name, the Rostov-on-Don (B-237) is the first trade-off model of the third generation submarines of the Varshavyanka class (Project 636) subs. The diesel-electric stealth sub is believed to be the quietest in the world. It also possesses an extended combat range and its relatively small size helps it maneuver in shallow waters.
The sub is armed with 533mm torpedoes and reportedly Kalibr-PL (submarine modification) water-to-surface cruise missiles. The sub weighs 4,000 tons, reaches underwater speeds of 20 knots (37kmp/h) and can dive to a depth of 300 meters. It has a 52-man crew and can spend 45 days at sea before needing to go to port. NATO has called this type of submarine a “black hole” for its ability to remain undetected.