North Korea could have ballistic missiles on submarines within two years

The country’s armed forces have already run a test launch of the missile, which Kim Jong-un watched from an offshore location

North Korean leader Kim Jong Un watches the test-fire of a strategic submarine underwater ballistic missile (not pictured) (Reuters )

North Korea's recent test-firing of a ballistic missile from a submarine was “very serious and concerning”, South Korea said on Monday, with one defence official suggesting Pyongyang could have a fully operational platform in two or three years.

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.

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

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.

The official, who asked not to be identified because of the sensitivity of the issue, said photographs from North Korea showing a rocket launched from the sea appeared to be authentic.

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.

Additional reporting by James Pearson

Reuters