An interesting March 29, 2023 Popular Mechanicsarticle that Russia's 6 diesel-electric Kilo submarines in its Black Sea Fleet (BSF) may be ordered to torpedo Ukrainian merchant ships and/or lay naval mines in the Black Sea. Russian subs and other units mistaking the nationality/flag of a ship in the Black Sea is possible...
Such naval mines, that can also be laid by Russian ships or aircraft, may threaten not only Ukrainian ships but ships of other nations bordering the Black Sea. Those other nations include Georgia and (a channel to) Moldova and NATO members Turkey, Rumania and Bulgaria. Also third country (flags of convenience) shipping could be sunk.
It is unclear whether destroying or damaging shipping of a NATO member by using torpedoes or naval mines would be considered an attack on NATO under Articles 4 and 5 of the NATO Treaty.
Escalation into a Russia-NATO confrontation might occur quickly even if accidental.
