North Korea successfully conducted a test of submarine-launched, underwater missiles on Saturday, according to state-run news agency KCNA.
The reclusive nation's latest military project was, according to KCNA, "developed on the personal initiative of Supreme Commander of the Korean People's Army Kim Jong Un."
Reports by the country's state media are usually close to impossible to verify but, if true, North Korea would be in violation of United Nations sanctions, which ban the country from acquiring missile and ballistic technology.
Saturday's missile tests were the latest in a number of military exercises by Pyongyang in the last few months.
In June last year, Kim Jong Un was filmed watching a rocket launch from an overlook while triumphant military music played in the background.
In January, a research group at Johns Hopkins University's U.S.-Korea Institute said on its website, 38 North, that in spite of speculation about Pyonyang planning to conduct a fourth nuclear test, satellite imagery found no evidence the country was going to do so. However, the report also said that "it is quite possible that one or more tunnels at the facility are sufficiently complete to be readied for another nuclear test should Pyongyang make the political decision to move forward."
In March, North Korea launched two mid-range ballistic missiles while the U.S. and South Korea were also conducting military tests in the region, drawing widespread international condemnation.
In an email to BuzzFeed News, the U.S. State Department strongly condemned North Korea's latest military exercise. It said:
"Launches using ballistic missile technology are a clear violation of multiple UN Security Council resolutions. We call 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 United States remains steadfast in its commitments to the defense and its allies. We will continue to coordinate closely with the ROK."