A ballistic missile North Korea fired from a submarine on Wednesday morning flew 500 km over the Sea of Japan and raised concerns over progress in Pyongyang's missile technologies after a failed test-firing last month. The missile fell into the sea inside Japan's air defense identification zone.

Chief Cabinet Secretary Yoshihide Suga told reporters that the submarine-launched ballistic missile (SLBM) was fired at 5:29 a.m. off Sinpo, North Korea. It soared in an east-northeasterly direction.

Tokyo filed a protest at the North's embassy in Beijing, saying the launch posed a "grave threat" to Japan and other countries in the region and violated U.N. Security Council resolutions, Suga said.