North Korean leader Kim Jong Un has supervised a test-fire of a submarine-launched ballistic missile, declaring it "the greatest success" that has put the country in the "front rank" of nuclear military powers.
North Korea fired a submarine-launched ballistic missile (SLBM) on Wednesday which flew about 500 kilometres, official media reported on Thursday.
The South Korean government and experts said the launch showed technical progress in the North's SLBM program.
If the North Korean regime continues to pursue its nuclear and missile capabilities and ignore severe economic difficulties of its people, it will bring about more severe sanctions and diplomatic isolation. It should also realise that it will hasten its self-destruction," the country's Foreign Ministry said in a statement.
"Our government is prepared with full readiness posture to protect our people and the safety of our country and will thoroughly respond to any North Korea's provocation."
Japanese Prime Minister Shinzo Abe called it "a threat to Japan's security and an unforgivable reckless act that significantly damages the peace and stability of the region".