The Italian Coast Guard has issued a notice valid until 14 February concerning a stretch of sea south of Sicily where a submarine is reportedly active.
No further details are given, but the fact that the area is indicated precisely (as are the dates) and that it is partly within Italian territorial waters suggests that the submarine in question is Italian or at least from an allied country.
There seems to be no link between this notice and the transit of Russian ships through the Strait of Sicily.
(thanks to Sergio Scandura)