South Korea has said that North Korea's recent test-firing of a ballistic missile from a submarine was "very serious and concerning", and that it will respond "mercilessly" to the threat.

Pyongyang's official KCNA news agency said on Saturday North Korea's leader, Kim Jong-un, oversaw the test-launch of the missile from an offshore location. Such a development could pose a new threat to the isolated country's neighbours and the United States.

"[South Korea] will completely sever the chain of provocations by mercilessly dealing with any provocations," South Korean Defence Minister Han Min-koo said in an emergency security meeting held on Monday to discuss the latest test, the Yonhap news agency reported.

"Retribution for provocations is an order from the people," Han said. "Our military will stand with solid military readiness and make flat-out efforts for citizens to lead their everyday lives at ease."

Kim Min-seok, spokesman for South Korea's defence ministry, on Monday urged North Korea to immediately stop developing SLBMs (submarine-launched ballistic missiles), "which hinder the stability of the Korean peninsula and Northeast Asia".

Questions over capability

He said North Korea still needed time to develop additional equipment in order to make its submarine-launched missile system fully operational.

However, a South Korean defence official said separately that North Korea could develop a fully operational submarine with ballistic missiles within two or three years.

 

Al Jazeera's Harry Fawcett, reporting from Seoul, said that while the South was taking the latest development very seriously, it was also trying to downplay the significance of the test.

"The defence ministry here says this first test seems only to have lobbed the missile a short distance above the surface," our correspondent said.

"But it’s likely to require a rethink of South Korea's strategy for defending itself from a possible nuclear strike." 

North Korea's state media often boasts of successful military and space accomplishments, including the launch of a functional communications satellite, which are not independently verified by outside experts.

It is believed to have launched a long-range rocket and put an object into orbit in December 2012, defying scepticism and international warnings not to pursue such a programme, which could be used to develop intercontinental missiles.

Source: Al Jazeera and agencies