A senior Pentagon official said the United States has never taken the military option off the table regarding North Korea, warning the North not to be "foolish" about acting aggressively.

At a forum on the South Korea-U.S. alliance in Washington on Wednesday, U.S. Deputy Assistant Secretary of Defense for East Asia Heino Klinck said the military exists to serve as a deterrent and as a stabilizing force.

Klinck said if deterrence of aggression fails, South Korean and U.S. forces will take joint action to "fight and win."

The U.S. official added while the Pentagon has provided the space for diplomatic efforts to denuclearize the North by not responding to its every single provocation, there may come a time when the response may be different.

As Pyongyang's year-end deadline for Washington to change its approach in their stalled denuclearization talks fast approaches, U.S. President Donald Trump hinted that military action may be exercised against Pyongyang if necessary.

Hours later, a senior North Korean official said leader Kim Jong-un was "displeased" by Trump's remarks, adding Pyongyang will promptly retaliate against any U.S. military action.

[Photo : YONHAP News]