As North Korea’s third nuclear test looms large, China is coming under all too familiar pressure to convince its unruly ally to change course or lend impetus to the next batch of international sanctions.

Beijing has for decades been propping up Pyongyang by supplying food, fuel and other necessities and providing political backing in the face of its provocations.

With stability being its top priority in the region, China’s patronage has also helped boost its clout over its reclusive neighbor.

Though China has downplayed its influence in the regime’s behavior, its role is taking on greater significance after the U.N. Security Council on Jan. 22 approved stronger-than-expected sanctions in punishment for the North’s December rocket liftoff.

“The Chinese don’t like the fact that the North Koreans continue with these provocations, which everyone blames China for not stopping,” Victor Cha, director of Asian studies at Georgetown University, told the Council on Foreign Relations in Washington.

“The Chinese don’t want to cut off (assistance), because that might create instability, and they don’t want to see the collapse of North Korea,” said Cha, who is also Korea Chair at the Center for Strategic and International Studies.

Beijing’s endorsement of Resolution 2087 marks a shift away from its normally rigid resistance to any compulsory measures against Pyongyang, triggering a rift between the two allies.

The North’s National Defense Commission on Jan. 24 blasted China for “abandoning without hesitation even elementary principles under the influence of the U.S., using arbitrary and high-handed practices and failing to come to their senses.”

On Tuesday, The Choson Sinbo, a Tokyo-based mouthpiece for the North Korean government, again criticized its big brother for being unable to correct “wrongful acts” by the U.S. and “conniving at intrusions on a certain country’s sovereignty.” Without explicitly naming China, the newspaper referred to a “big country” whose “rapid economic growth elevated its international standing.”

China, for its part, shot back by calling for a cut in assistance in response to another atomic explosion in an editorial carried by state-run Global Times on Jan. 25.

The country’s customs agency has reportedly tightened inspections of cargo shipped to and from North Korea through main routes along the border.

Other news reports suggest that Beijing’s Foreign Ministry has repeatedly called in North Korean Ambassador Ji Jae-ryong since the regime on Jan. 24 threatened to fire more long-range rockets and conduct a “high-level nuclear test targeting the U.S.”

While the war of nerves led some to paint a rosier picture for future global cooperation in taming Pyongyang’s nuclear ambitions, many experts doubt any potential turnaround in Chinese North Korea policy or their “blood” relationship.

China’s consent to the new resolution reflects its effort to engage with the U.S. and rein in an increasingly wayward North Korea, according to Yoo Hyun-jung, a researcher at Sejong Institute.

“China is seeking to advance its relations in particular with the U.S. under the second-term Obama administration. So it’s highly possible that China had seen its objection to the sanctions as negating such attempts,” she said in a commentary.

“At the same time, China must feel the need for warning messages to North Korea’s obstinate behavior given its two rocket launches in April and December in defiance of China’s dissuasion.”

Bonnie Glaser, a China specialist at the Washington-based CSIS, has also predicted that Xi Jinping’s incoming government is unlikely to undertake any fundamental shift in North Korea policy, preoccupied with domestic hurdles including political reform, a cooling economy and growing middle class demand.

“In my view, even a third nuclear test by North Korea is not likely to cause a major change in Chinese policy,” she told The Korea Herald earlier.

“The Chinese are currently seeking to promote economic reform in North Korea, to strengthen China’s ties with North Korea and potentially increase Chinese leverage and influence, and ensure that North Korea remains stable. These are enduring interests.”

South Korea, the U.S. and other countries are calling for China’s extra efforts to discourage the North from the high-stake plan. They have vowed additional, more stifling measures such as targeting its financial assets or sea transport, should the communist state detonate another fission bomb.

Lim Sung-nam, Seoul’s special representative for Korean Peninsula peace and security affairs, met with his Chinese counterpart, Wu Dawei, in Beijing on Tuesday to discuss the imminent atomic test.

Lim is believed to have requested Beijing’s “all-out” diplomatic offensive to keep detonation at bay and suggested reinforcing policy coordination also with other neighbors even if it fails.

The two sides shared the view that another nuclear test would pose a threat to peace and stability and reaffirmed the goal of denuclearization of the peninsula, diplomats said.

Glyn Davies, Washington’s special representative for North Korea policy, also visited the Chinese capital on Jan. 25 to meet with Wu, Vice Minister of the Central Committee’s international department Liu Jieyi and other executives.

Lim, Davies and Wu are chief negotiators for a six-nation dialogue aimed at disarming North Korea.

By Shin Hyon-hee (heeshin@heraldcorp.com)