Seoul: Recent satellite imagery suggests North Korea may be building a new, larger submarine for ballistic missiles, a US think tank has said, as the isolated state pushes its nuclear weapons programme.
The news comes after the North in August test-fired a submarine-launched missile (SLBM) 500 kilometres (around 300 miles) towards Japan, which leader Kim Jong-Un said put the US mainland and the Pacific within striking range.
"Commercial satellite imagery strongly suggests that a naval construction program is underway at North Korea`s Sinpo South Shipyard, possibly to build a new submarine," the US-Korea Institute at Johns Hopkins University said on its closely-watched website, 38 North.
"If this activity is indeed to build a new submarine, it would appear to be larger than North Korea`s GORAE-class experimental ballistic missile submarine, which has a beam of approximately 7 meters."
Analysts say that while Pyongyang has made faster progress in its SLBM system than originally expected, it is still years away from deployment.
A proven SLBM system would take North Korea`s nuclear strike threat to a new level, allowing deployment far beyond the Korean peninsula and a "second-strike" capability in the event of an attack on its military bases.
South Korea`s military authorities believe Pyongyang is eyeing a submarine capable of carrying multiple SLBMs, to replace an existing experimental submarine used for the August test, according to Seoul`s Yonhap news agency.
North Korea is barred under UN resolutions from any use of ballistic missile technology, but this year alone it has test-fired more than 20 missiles and carried out two nuclear tests.
Its fifth and most powerful nuclear test on September 9, when Pyongyang detonated what it said was a miniaturised atomic bomb, provoked worldwide condemnation and prompted the UN Security Council to begin work on a new sanctions resolution.
Also this month, the North claimed to have successfully ground tested a new, high-powered rocket engine, a move Seoul said was designed to showcase its progress towards being able to target the US east coast.