Two huge Oscar II class submarines, with their 24 large Granit missiles (each) may be confronting two Western carrier groups. See the tiny human figures (bottom, right) for scale. See here for larger image.
Claims that Western forces are still hunting two Oscar II submarines in the small Mediterranean Sea would be incorrect. These subs would have been detected very quickly in the small sea environment. At 25 years old, the huge, 19,400 tons (submerged) are easily spotted with active sonars. Also each Oscar is propelled by two aging OK-650 naval reactors, developed in the 1970s, which are likely to be very noisy.
Oscar II submarine comparative noise lever (Courtesy FAS). FAS also reports (upper diagram here) Akula II's have about the same noise level as Improved Los Angeles class (688i). Inconclusive. Which returns Oscar II to 1970s noise, returning to their 1970s reactor noise.
If these Oscars are confronting US and French carrier groups in the Mediterranean Sea the carrier escorts, ASW destroyers, frigates, corvettes, ASW MPAs and helicopters would all have played a part in detecting and tracking the Oscars.
Once detected just one Western ASW corvette per Oscar could tail the Oscar, using the corvette's active sonars, from one end of the Med to the other.
It may be the confronting nature of the Oscars that prompted the West to publicise the activities of these Oscars. Ordinarily activities of enemy subs are kept secret.
An Oscar firing some Granit missiles. The Granits are arranged and fired diagonally. This may be required for flight dynamics. Diagonal firing also has tactical benefits for the Oscar, ie. it can keep moving (perhaps ready to fire torpedos) rather than having to stop like an SSBN firing SLBMs. (Artwork courtesy Federation of American Scientists).
"NATO is Hunting Russia's "Carrier Killer" Submarines'
The subs are thought to be stalking two NATO carrier battle groups operating nearby.
NATO's anti-submarine forces are currently hunting one, and possibly two, Russian submarines in the eastern Mediterranean. The submarines, Oscar-II class guided missile boats, was designed to take out aircraft carriers in wartime. Two NATO carriers are operating off the coast of Syria….USS Eisenhower and the French Charles De Gaulle …in the eastern Med…[operating against IS in Syria]….
The Oscar's firepower lies in its 24 [very large, supersonic] P-700 Granit missiles…
A Granit being unloaded from the destroyed Oscar II submarine Kursk (Photo courtesy Air Power Australia). The P-700 Granit/3M45/SS-N-19 "Shipwreck" with its 7 tonne launch weight can fly 300 nautical miles, with an end-run of Mach 2.5. Granits are also deployed on Kirov class battlecruisers (only "Peter the Great" (in English) is active) and on the aircraft carrier Admiral Kuznetsov.
Miniaturisation of modern electronics and of (nuclear and conventional) warheads is permitting the gradual phase-out of the large Granit concept in favour of the only(!) 3 tonne BrahMos / P-800/Oniks/Yakhont/SS-N-26 "Strobile".