The United States said Saturday it is a violation of U.N. Security Council resolutions for North Korea to launch ballistic missiles after the communist nation claimed it successfully test-fired a ballistic missile from a submarine.



"We closely monitor North Korean activities and the situation on the Korean Peninsula, especially North Korean military activities," a State Department spokesperson said. "Launches using ballistic missile technology are a clear violation of multiple U.N. Security Council resolutions."



On Saturday, the North claimed it successfully carried out an underwater test-fire of a submarine-launched ballistic missile. If confirmed, it would be the country's first test-fire of a ballistic missile from a submarine.



South Korean officials said, however, that the North's submarine-launched missile was more of a test for an ejection rather than firing, since the missile is assumed to have flown only about 100 meters after it soared from the waters.



"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 State Department spokesperson said.



"The United States remains steadfast in its commitments to the defense of its allies. We will continue to coordinate closely with the ROK (South Korea)," the official said.



Intelligence sources from Seoul and Washington have said that the North has been developing a submarine-launched ballistic missile (SLBM), warning that it can be a fresh threat to the security of the Korean Peninsula.



North Korea has conducted three nuclear tests so far, in 2006,2009 and 2013. The country has also conducted a series of long-range missile or rocket launches since 1998. In its latest launch in late 2012, the North succeeded in putting a satellite into orbit.



Experts have warned that it is only a matter of time until the North develops nuclear-tipped missiles. (Yonhap)