South and North Korea fire missiles hours apart, raising prospect of arms race

The South's submarine-launched missile test came hours after it said the nuclear-armed North fired two ballistic missiles into the sea.

South Korea's first underwater-launched ballistic missile is test-fired from a 3,000-ton-class submarine at an undisclosed location in South Korea Source: South Korea Defense Ministry

South Korea successfully test-fired a submarine-launched ballistic missile Wednesday, becoming only the seventh country in the world with the advanced technology and raising the prospect of a regional arms race.

The test, supervised by President Moon Jae-in, came hours after nuclear-armed North Korea fired two ballistic missiles into the sea, according to the South's military - prompting Washington to brand Pyongyang's action a provocative "threat" to Asian neighbors.

South Korea's test is a strategic advance for Seoul. It has been strengthening its military capabilities to counter the threat posed by the North, which is under international sanctions for its nuclear weapons and ballistic missile programs.

The unidentified type of missiles were fired from central inland areas of the North. Source: Getty Images AsiaPac

The South's missile was fired underwater from its newly commissioned submarine Ahn Chang-ho, and flew the planned distance before hitting its target, the presidential Blue House said.

With the successful tests, South Korea now has "sufficient deterrence to respond to North Korea's provocations at any time", Mr Moon said, adding that his country should continue increasing its weapons programs to "overwhelm North Korea's asymmetric power".

Within hours he was rebuked by North Korean leader Kim Jong Un's influential sister Kim Yo Jong, who lambasted him for making a "thoughtless utterance" and incorrectly accusing the North of "provocation".

Seoul has an "illogical and stupid habit of describing its act as a just one supporting peace and describing our act of similar nature as the one threatening peace," she said in a statement carried by Pyongyang's official Korean Central News Agency (KCNA).

Earlier in the day, the North fired "two short-range ballistic missiles" from South Pyongan province into the sea off its east coast, Seoul's Joint Chiefs of Staff said.

On Thursday, KCNA reported the missile launches had been a firing drill for a "railway-borne missile regiment", with the aim of increasing "the capability of dealing an intensive multi-concurrent blow at the forces posing threats to us".