North Korea’s military Tuesday threatened archrival South Korea with imminent “sledge-hammer” retaliation unless Seoul apologizes for anti-Pyongyang protestors burning effigies of its revered leaders."Sledge-hammer" retaliation - let's see, is that better or worse than a "nuclear sea of fire?"
South Korea called the North’s ultimatum “regrettable” and vowed a tough response to any military provocation.
You keep using that word. I do not think it means what you think it means.