A US Navy SSN sank an Iranian ship with a torpedo.

This STRONGLY suggests that the Iranian navy sortied a kilo class diesel electric submarine towards the USS Abraham Lincoln Carrier Strike Group and a US Navy attack submarine sank it.

CLARIFICATION: the last time a US NAVY Submarine used a torpedo to get a kill was WWII.

The last time ANY submarine killed a warship with a torpedo prior to today was HMS Conqueror, a Royal Navy SSN, sank the Argentine cruiser General Belgrano in 1982 during the Falklands war.