Seoul - Nuclear envoys from South Korea, Japan and the United States met in Seoul on Wednesday, seeking a way forward to revive long-stalled, six-party talks with North Korea on its nuclear weapons programme.
The effort comes as North Korea ramps up its nuclear rhetoric, boasting last week of its ability to miniaturise a nuclear warhead to fit on high-precision, long-range rockets.
Hwang Joon-kook, South Korea's special representative for Korean Peninsula peace and security affairs, said Wednesday's dialogue was particularly timely given what he described as an "uncertain and tense" situation in North Korea.
"We are also facing the continuing advancement of North Korea's nuclear and missile capabilities," Hwang said before the meeting with Sung Kim, US special representative for North Korea policy, and Junichi Ihara, a regional director-general in the Japanese foreign ministry.
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As well as last week's claim that the nation was capable of miniaturising nuclear warheads, Pyongyang recently hailed the "historic" test of a submarine-launched ballistic missile (SLBM).
But outside experts said state media reports of the test were exaggerated and estimated that the North was still years from developing a genuine SLBM capability.
Meanwhile, questions over the stability of Kim Jong-Un's leadership re-surfaced after South Korean intelligence reported that his defence minister had been purged and likely executed.
Against this background, efforts have been gathering pace to find a way back to the six-party talks, between North and South Korea, Japan, the United States, China and Russia.
The six-party forum was set up to persuade North Korea to give up its nuclear weapons in return for economic and diplomatic benefits, as well as security guarantees, but has not met since December 2008.
After Wednesday's dialogue in Seoul, the South Korean and US envoys were set to fly to Beijing to meet with their Chinese counterpart Wu Dawei.
There is growing pressure for the international community to try a new approach with North Korea, which has pushed ahead with its nuclear and missile programmes despite multi-layered UN sanctions and diplomatic isolation.
The United States and South Korea insist that the North must show a tangible commitment to denuclearisation before significant talks can resume, a stance some analysts find too rigid.
"Unless they lower the bar for North Korea to resume the talks, China is unlikely to take the initiative," said Hong Hyun-Ik of the Sejong Institute think-tank in Seoul.
China is North Korea's largest investor, aid donor and trade partner, as well as its main diplomatic protector.
But relations have cooled significantly since Xi Jinping became China's president in 2012 and North Korean leader Kim Jong-Un took power following the death of his father in late 2011.
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Xi and Kim have kept their distance since each assumed power and the Chinese leader's first visit as head of state to the Korean peninsula was to the capitalist South last year, rather than the North.
North Korea carried out nuclear tests in 2006, 2009 and 2013, and has an active ballistic missile development programme, although expert opinion is split on how much progress it has made.
A recent report by US researchers warned that the North was poised to expand its nuclear programme over the next five years and, in a worst-case scenario, could possess 100 atomic arms by 2020.