China warned against "troublemaking" on its doorstep, in an apparent rebuke to North Korea, and the United States said it was postponing a missile test to help calm high tension on the divided Korean peninsula.
The North, led by 30-year-old Kim Jong-un, has been issuing vitriolic threats of war against the United States and US-backed South Korea since the United Nations imposed sanctions in response to its third nuclear weapon test in February. Pyongyang's anger appears heightened by US-South Korean joint military exercises.
But most analysts say it has no intention of starting a conflict that would bring its own destruction and instead is out to wring concessions from a nervous international community.
The North told diplomats late last week to consider leaving Pyongyang because of the tension, but embassies appeared to view the appeal as more rhetoric and staff have stayed put.
South Korea said it was ready for any kind of action that the North's unpredictable leaders might make - including a possible missile launch - by Wednesday, after which the North said it could not guarantee diplomats' safety.
China, North Korea's sole financial and diplomatic backer, has shown growing irritation with Pyongyang's warnings of nuclear war. Chinese president Xi Jinping, addressing a forum on the southern island of Hainan, did not name North Korea but said no country "should be allowed to throw a region and even the whole world into chaos for selfish gain".
Stability in Asia, he said, "faces new challenges, as hot spot issues keep emerging and both traditional and non-traditional security threats exist".
Chinese foreign minister Wang Yi expressed similar frustration in a statement late yesterday, relating a telephone conversation with UN secretary-general Ban Ki-moon.
"We oppose provocative words and actions from any party in the region and do not allow trouble making on China's doorstep," Mr Wang said, according to a ministry statement on its website.
The ministry expressed "grave concern" at rising tension and said China had asked North Korea to "ensure the safety of Chinese diplomats in North Korea, in accordance with the Vienna Convention and international laws and norms". China's embassy, it said, was "understood" to be operating normally in Pyongyang.
Australian prime minister Julia Gillard, addressing the Hainan forum, said avoiding conflict on the peninsula was vital. "There, any aggression is a threat to the interests of every country in the region," she said.
British foreign minister William Hague said North Korea's nuclear ambitions had to be taken seriously. Interviewed by Sky News, he said the international response "should also be very clear, very united and calm at all times because it's important not to feed that frenetic rhetoric that we've seen over the last few weeks".
Switzerland's foreign ministry offered to mediate, saying it was "always willing to help find a solution, if this is the wish of the parties, such as hosting meetings between them".
Kim, the third member of his dynasty to rule North Korea, is thought to have spent several years in Switzerland being educated under a pseudonym. He took over in December 2011 after the death of his father Kim Jong-il, who confronted South Korea and the United States throughout his 17-year rule.
The US said it would delay a long-planned missile test scheduled for next week out of California "to avoid any misperception or miscalculation," given tensions with North Korea.
The unusual precaution by the United States follows a barrage of hostile rhetoric from North Korea and reports in the South that Pyongyan had moved two medium-range missiles to a location on its east coast.
The White House said on Friday it would "not be surprised" if the North staged another missile test. At the same time, officials have said there are no signs Pyongyang is gearing up for war, such as large-scale troop movements.
The US decision will delay a test of the Minuteman III intercontinental missile, which had been scheduled for next week out of Vandenberg Air Force Base in California.
"This is the logical, prudent and responsible course of action to take," an official said, speaking on condition of anonymity.
The US official said the test had been unconnected to "anything related to North Korea" and added that another test launch could be expected next month. The United States remained fully prepared to respond to any North Korean threat, the official said.
Analysts are looking anxiously ahead to April 15th, the birthday of Kim Il-sung, North Korea's founder and the grandfather of its current leader, Kim Jong-un. The anniversary is a time of mass celebrations, nationalist fervour and occasional demonstrations of military prowess.
Reuters