North Korea says it has successfully test-fired a newly developed ballistic missile from a submarine, in what would be the latest display of the country's advancing military capabilities.
North Korean leader Kim Jong-Un, who personally oversaw the test on Saturday, called the newly developed missile a "world-level strategic weapon", according to a report by the official KCNA news agency.
The agency quoted Kim as saying the Korean military now possessed a weapon "capable of striking and wiping out in any waters the hostile forces infringing upon [North Korea's] sovereignty and dignity."
Saturday's test would violate multiple UN Security Council resolutions banning North Korea from using ballistic missile technology.
The US called on North Korea "to refrain from actions that further raise tensions in the region and focus instead on taking concrete steps toward fulfilling its international commitments and obligations," the State Department said.
While South Korea's presidential Blue House held an emergency national security council meeting to review the threat and discuss possible countermeasures.
Pyongyang has issued three warnings over the past week that it will fire on sight at South Korean navy patrol boats it accuses of violating the disputed Yellow Sea border on the west side of the divided peninsula.
North Korea's small submarine fleet is comprised of largely obsolete Soviet-era and modified Chinese vessels, but suggestions that it was experimenting with a marine-based missile system have been around for a while.