North Korea has unveiled for the first time what it says is a nuclear-powered submarine under construction, a weapons system that can pose a major security threat to South Korea and the US.

North Korea’s newly unveiled nuclear-powered submarine, reportedly made with Russian technology, could pose a major security challenge to neighbour South Korea and its ally the US, experts said.The Korean Central News Agency on Saturday released photos of what it called an under-construction “nuclear-powered strategic guided missile submarine",

North Korea has long vied for nuclear-powered submarines, which would allow it to fire missiles from underwater. Advanced detection of the weapons is difficult, making the country’s construction of the warships worrisome.