The U.S. State Department has condemned North Korea's launch of a ballistic missile below the de facto inter-Korean maritime border as a "reckless decision."

The department released a statement on Wednesday in response to the more than 20 missiles and 100 artillery shells fired by North Korea earlier in the day, with one of the missiles falling in waters south of the Northern Limit Line.

The statement said that these launches are in violation of multiple UN Security Council resolutions and pose a threat to peace and stability in the region, while reaffirming the U.S.' ironclad commitment to the defense of South Korea and Japan.

In a separate press briefing on Wednesday, department spokesperson Ned Price said that Washington remains concerned about the potential for further provocations, including a seventh nuclear test, adding that Pyongyang may be prepared to conduct a nuclear test "at any time."

Price then warned that should the North go forward with a seventh nuclear test, there would be additional costs and consequences.