China on Thursday warned its ally North Korea of unspecified "serious consequences" if it carries out its first nuclear weapons test _ Beijing's sharpest rebuke yet in response to Pyongyang's stated intentions.
China's stern remark came amid a growing international outcry about North Korea's announcement Tuesday that it would conduct an unprecedented nuclear test.
A newspaper with strong ties to the North, meanwhile, said the regime was not bluffing.
Chinese Ambassador to the United Nations Wang Guangya said "no one is going to protect" North Korea, if it goes ahead with "bad behavior."
"I think if North Koreans do have the nuclear test, I think that they have to realize that they will face serious consequences," Wang said Wednesday.
The comment was China's most forceful public response yet to its ally's announcement Tuesday, and a break with Beijing's usual conciliatory strategy of avoiding warnings to or criticism of the North.
Beijing _ the North's main source of food and fuel aid _ has appealed for restraint but hasn't said what it might do if Pyongyang detonates a bomb.
The rebuke spells trouble for North Korea, which faces a relatively united front against its nuclear aspirations, in sharp contrast to the fractured reaction to a series of North Korean missile tests in July. At that time, China accused Japan of overreacting in calling for sanctions.
On Thursday, a pro-North Korean newspaper based in Japan warned that Pyongyang is not bluffing with talk of the test.
"The nuclear test statement was not empty language, but announced on the premise of action," the Choson Sinbo said. "Carrying out a nuclear test is an inevitable conclusion ... under a condition where (the country) declared possession of nuclear weapons in February last year."
The paper, run by an association of North Korean residents in Japan, is not part of the North's official media but is considered one of its propaganda tools. Its articles are believed to reflect the country's position.
It hedged its warning by saying the crisis can be overcome if the U.S. begins to take action toward denuclearization of the Korean Peninsula with "the same goal" of North Korea.
The report did not say whether negotiations could forestall a nuclear test, or what crisis it was referring to. But North Korea said Tuesday's that it has the goal of mending "hostile relations" with the U.S. and eventually establishing a nuclear-free Korean Peninsula.
Japan and South Korea have said there is no sign of an imminent test, but a U.S. intelligence official, speaking on condition of anonymity due to the highly sensitive nature of the situation, said the United States is now seeing the movement of people and materials at a possible test site.
However, similar activity was seen a couple months ago, when no test occurred. The official also said observers do not have a baseline for comparison, because North Korea has never performed a nuclear test.
On Tuesday, the North rattled the world by announcing it would conduct the test in a step toward building its nuclear arsenal, which it views as a necessary deterrent against any U.S. attack. The U.S. has repeatedly denied any intention of invading.
Looming on the horizon are possible dates that North Korea may want to commemorate with such a test, including Sunday _ the ninth anniversary of national leader Kim Jong Il becoming secretary-general of the country's Workers Party of Korea, and Tuesday's 61st anniversary of the party's founding.
North Korea often times actions with dates to maximize propaganda impact, as it did by testing missiles _ including a long-range model believed capable of striking the U.S. _ on American Independence Day, July 4.
A separate report Thursday said Kim has dropped from public view amid rising tensions.
South Korea's Chosun Ilbo newspaper reported that Kim had not been seen in public for 20 days, and noted that the enigmatic leader has similarly remained aloof ahead of other provocative acts by his government, such as the missile tests.
Kim may be lying low for fear of U.S. military action, or to monitor the international repercussions of the country's announcement, the newspaper suggested.
Kim dropped from sight for about a month in 1998 before North Korea test-fired a long-range missile that flew over Japan, the newspaper said.
In 2003, he reportedly dropped from view for seven weeks after his country quit the Nuclear Nonproliferation Treaty. He disappeared for about a month after his country test-fired a series of missiles in July.
Ahead of the current spike in tension, the North's official Korean Central News Agency last reported on Kim's public activity on Sept. 15, saying he visited the scenic Diamond Mountain area near the South Korean border. He had made five previous appearances that month.
The North claims it has nuclear weapons, but has not performed any known test.
Some experts believe the North has enough material to build at least half a dozen nuclear bombs, but there are doubts as to whether it could deliver them accurately on a warhead.