North Korean leader Kim Jong Un celebrated a military submarine's launching of a ballistic missile, calling the test fire "the greatest success" to date, according to a state run news outlet Thursday.

"He noted with pride that the results of the test-fire proved in actuality that the DPRK (Democratic People's Republic of Korea) joined the front rank of the military powers fully equipped with nuclear attack capability," state-run media outlet KCNA reported.

Even the South Korean government said the launch showed technical progress within DPRK's missile program.

A North Korean submarine launched a ballistic missile off the coast of Sinpo early Wednesday local time, the Pentagon confirmed late Tuesday.

The presumed KN-11 missile covered 300 miles before landing in the Sea of Japan, U.S. Strategic Command confirmed. The North American Aerospace Defense Command said the launch did not pose a threat to the U.S., but Defense officials will continue to monitor the communist country.

"The men and women of USSTRATCOM, NORAD and U.S. Northern Command, and U.S. Pacific Command remain vigilant in the face of North Korean provocations and are fully committed to working closely with our Republic of Korea and Japanese allies to maintain security," Gary Ross, U.S. Navy commander, said in a statement.

North Korea has tested more than half a dozen ballistic missiles since the beginning of the year, despite a United Nations' Security Council resolution to halt all nuclear-related tests.