North Korea is believed to be on its way to miniaturizing nuclear weapons, the South Korean defence ministry said Friday.
"North Korea has conducted nuclear tests three times. Doubts still remain over whether it has a capability to make small, light (nuclear) warhead that can be mounted on missiles," Kim Min-seok, spokesman at the Ministry of National Defence, told reporters at a press briefing.
Kim, however, noted that North Korea was estimated to be on its way to miniaturizing the nuclear warheads.
His comments came in response to media reports quoting US House Representative Doug Lamborn as telling a House hearing that North Korea has the capability to deliver nuclear weapons with ballistic missiles. Lamborn cited a classified report by the Defense Intelligence Agency (DIA).
Pentagon spokesman George Little said in a statement that it would be "inaccurate" to suggest that North Korea has fully demonstrated its capability to launch a nuclear-armed missile.
Neither the White House nor Chairman of the Joint Chiefs of Staff Martin Dempsey, who attend the hearing, has made any comments on the DIA assessment and Lamborn's statements.
Tensions have been running high on the Korean Peninsula after North Korea conducted its third nuclear test Feb 12 in reaction to the joint military drills between Seoul and Washington.
Pyongyang said it would restart operations at its Yongbyon nuclear complex, including a uranium enrichment plant and a five-megawatt graphite moderated reactor that had been "mothballed and disabled" since October 2007.