While North Korea is thumbing its nose at the international community by announcing a planned test of a long-range rocket following last month's nuclear test, China, the North's key economic and diplomatic lifeline, acknowledged on Wednesday that it can't thwart the looming launch. 

North Korea's fourth nuclear test on Jan. 6 came nearly four months after Liu Yunshan, the Chinese Communist Party's fifth-ranked leader, held talks with the North's leader Kim Jong-un in Pyongyang. 

The talks between Kim and Liu failed to dissuade North Korea from conducting a nuclear test, which has been widely viewed as a slap in the face for China. 

China has expressed displeasure over the North's nuclear and missile programs, but resisted calls for tougher new sanctions against North Korea following the latest nuclear test. 

Many analysts believe that China's Communist Party leadership won't exert enough leverage on North Korea because a sudden collapse of the North's regime could threaten China's own security interests.

Analysts say North Korea won't feel any repercussions from the latest nuclear test and the upcoming rocket launch because the North's Kim clearly understands that Beijing fears pushing Pyongyang too hard could lead to its collapse, instability on its border and ultimately the emergence of a pro-U.S. nation next door.

In response to North Korea's announcement of its planned rocket launch, China's foreign ministry spokesman Lu Kang used unusually candid language, saying "We don't want to see any escalation of tensions. But, if the relevant country insists on doing so, we are not able to stop them." 

Lu blamed the United States for raising tensions and repeated that China is not the source of North Korea's nuclear issue. 

"In response to some countries' outcry for pressure and sanctions, North Korea conducted one nuclear test after another," Lu said. 

"In this sense, North Korea did slap some country across the face. As for whose face North Korea did slap, I think the country itself knows well," Lu said.

North Korea's notification of its planned rocket launch to U.N. agencies coincided with a visit by China's top nuclear envoy, Wu Dawei, to Pyongyang. 

Lu said Wu will "exchange views with the North Korean side on the current situation of the (Korean) Peninsula," describing Wu's visit to Pyongyang as a "bilateral exchange between the two sides." 

Chang Yong-seok, a senior researcher at the Institute for Peace Affairs at Seoul National University in Seoul, said he does not expect the Chinese envoy to persuade North Korea to halt the coming launch. 

"Although special envoy Wu Dawei visited North Korea, his visit is unlikely to affect the upcoming launch," Chang said. 

"Currently, North Korea is seen completing technical preparations for a rocket launch. So, North Korea will proceed with the launch if certain conditions, including weather, are met," Chang said. (Yonhap)