North Korea's nuclear program is a "major challenge to global security", US Secretary of State John Kerry told his Chinese counterpart Wednesday, urging Beijing to increase pressure following its wayward neighbor's latest atomic test. 


The North's pursuit of atomic weapons is "one of the most important issues for the security of the United States of America", the top US diplomat told Wang Yi on the last stop of his Asian tour. 


A US official said earlier the issue would be at the top of Kerry's agenda, adding: "The Secretary has made no secret... of his conviction that there is much more that China can do by way of applying leverage (on Pyongyang)." 


China is North Korea's chief diplomatic protector and economic benefactor, but those ties have become strained in recent years as Beijing's patience wears thin with Pyongyang's unwillingness to rein in its nuclear weapons ambitions. 


After the latest test on January 6 -- which Pyongyang said was a miniaturized hydrogen bomb, a claim largely dismissed by experts -- China said it "firmly opposes" the North's actions and summoned its diplomats for "solemn representations". 


Nevertheless, the Asian power has proven reluctant to follow Washington's lead on the issue and no substantive actions towards the North have been announced. 


Wang welcomed the fact that Kerry's trip had taken in a number of Asian countries, saying visiting them could help him understand the continent. "It can help you listen to voices more objectively," he added. 


As Kerry arrived in Beijing on Tuesday, the state-run China Daily ran an article headlined: "Experts have low hopes for Kerry's China trip." 


Before Wednesday's meeting, the official news agency Xinhua issued a commentary blaming the US's "uncompromising hostility" and "Cold War mentality" for the situation on the Korean peninsula. 


Washington's actions, such as flying a nuclear-capable B-52 bomber close to the inter-Korean boder, were heightening the North's "sense of insecurity and thus pushing it towards reckless nuclear brinkmanship", it added. 


China's leverage over Pyongyang is mitigated, analysts say, by its overriding fear of a North Korean collapse and the prospect of a reunified, US-allied Korea directly on its border

Source: NNA