Almost every nation state that touches water has submarines of one kind or another.
That's what NK thought when they attacked and sunk the ROKS Cheonan. Who'd blame them if nobody saw the submarine?
In practice, though, all major local players are on board. Turkey is the least compliant one, but they were put on notice today by a small "navigational mistake" of a Su-30. Russia apologized, of course - words are cheap.
The USA is the only player who is not entirely in agreement about what's happening. We can also sink the ship, as there is no shortage of submarines [so far.] However it would be very obvious who did it, and - even if it doesn't start the World War III - one of our aircraft carriers may one day, entirely unexpectedly, hit a large floating mine that wasn't there a minute ago. Stones, glass houses... Among all the leaders today, Putin is probably not the safest to cross.