The military option has always been on the table in dealing with North Korea, says a senior U.S. military official.
The Defense Department's Deputy Assistant Secretary for East Asia, Heino Klinck, told reporters on Wednesday that the Pentagon has, until now, provided space for diplomatic efforts with North Korea but this could shift.
He explained that the military exists to serve as a deterrent against war, but if deterrence fails, then the military has to fight and win.
Klinck went on to warn Pyeongyang, saying it'd be foolish for the North to act aggressively and the North knows it.
The thorny response from the U.S. comes shortly after a top North Korean military officer lashed out at Washington earlier in the day.
The chief of the North Korean military's general staff, Pak Jong-chon, issued a statement saying Kim Jong-un was greatly "displeased" by President Trump's remark that Washington would use military force against the North if it has to.
He stressed if the U.S. does do that, then Pyeongyang will "also take prompt corresponding actions."
This is the first time the North Korean army's number two has spoken out himself.
The exchange of rhetoric between Washington and Pyeongyang began as North Korea continued to press the U.S. to change course and make concessions to the North by the year's end.
That's the North's unilaterally set deadline for nuclear negotiations after which it has stressed it will take a "new path" if the talks don't bear fruit.
The North seems to be devising its plan for next year.
Kim Jong-un has shown that he's mulling over a big political decision by visiting Mount Baekdu earlier this week.
The regime has also scheduled a major ruling party gathering later this month, which determines the party's policy.
Oh Jung-hee, Arirang News.