As Japan warned that the threat posed by North Korea's nuclear weapons program has entered "a new stage," China has come down on the side of economic sanctions against the isolated Pyongyang regime.
But political analysts in China and Taiwan said the move may not be enough to ensure Pyongyang's return to the negotiating table.
In a report released on Tuesday, Japan's defense ministry warned that North Korea may already have achieved the miniaturization of nuclear weapons necessary to launch a long-range nuclear missile strike.
"Since last year, when it forcibly implemented two nuclear tests and more than 20 ballistic missile launches, the security threats have entered a new stage," it said in its annual defense white paper.
North Korea under supreme leader Kim Jong Un has carried out a string of missile tests since the beginning of the year, including two intercontinental ballistic missiles (ICBMs) which landed off the west coast of Japan.
Japan's warning comes after the United Nations Security Council unanimously voted through a new round of sanctions against Pyongyang at the weekend.
North Korea slammed the new U.N. sanctions as "fabricated" and warned there would be "strong follow-up measures."
The sanctions, which include a ban on coal and other North Korean exports worth over U.S.$1 billion, also had the backing of Beijing, which said that they were a "price worth paying."
Chinese Foreign Minister Wang Yi said China, as North Korea's closest trading partner, will pay the biggest price for the new United Nations sanctions, but vowed to enforce them.
The sanctions could slash Pyongyang's U.S.$3 billion annual export revenue by a third, analysts said.
Analysts said Wang Yi's comments weren't only directed at North Korea, but also at vested interests in the ruling Chinese Communist Party's own ranks, however.
"[President] Xi Jinping and U.S. President Donald Trump may have agreed that mainland China will reduce trade with North Korea when they met back in April, but according to video sent by internet users in [the border city of] Dandong, there is a never-ending stream of transportation crossing the Yalu River Bridge, and Sino Korean trade is still increasing daily," journalist Zhao Yan wrote in a commentary for RFA's Cantonese Service on Monday.
Video of the Yalu River Bridge posted to YouTube by user Xi Tianqi showed a line of trucks moving slowly across the bridge.
According to the Korea Trade and Investment Promotion Corporation (KOTRA) North Korea's foreign trade dependence was at a record high of 92.5 percent in 2016. By comparison, North Korean trade dependence on Russia was 1.2 percent.
"There is no way that Fatty Kim can run the North Korean economy without the support of the Chinese government," Zhao said, using an online nickname commonly used in China for Kim Jung Un. "But what is worth noting is that Sino-Korean trade has continued to expand ever since ... President Hu Jintao came to power [in 2002]."
Zhao said recent corruption probes into Wang Min, former party secretary for the northeastern province of Liaoning, which borders North Korea, could be linked to Xi's bid to reduce trade with North Korea.
"But [Chinese] officials are driven by vested interests, and Xi Jinping's anti-corruption campaign seems powerless to stem the temptation of skimming off some of Fatty Kim's cash on the part of mainland Chinese officials," Zhao wrote. "If this weren't the case, then we wouldn't have a ceaseless flow of trucks crossing that river."
But To-hai Liou, foreign policy expert at Taiwan's Chengchi University, said the stakes are high for Xi's central government in Beijing, too.
"If the United States were to launch an attack on North Korea, this would diminish China's authority," Liou said. "It goes without saying that it would probably start another Korean war, or instability in northeast Asia, not to mention the possible collapse of the North and a flood of refugees in China."
The sanctions raise the possibility that North Korea could be forced to return to the negotiating table.
But Wang Sheng, a Korean expert at Jilin University in northeastern China, said he isn't optimistic about that prospect.
"There will need to be three-party talks between China, the U.S. and the North, or four-party, between the U.S., China and both North and South Korea, before they can move to six-party talks [including Russia and Japan]," Wang said. "But it is pretty clear that North Korea won't be curbed by China."
"What the North really wants is for formal diplomatic ties to be set up with the United States, and a [bilateral] dialogue. This has been its position all along," he said.
But he said progress could be hampered by demands from Pyongyang for a halt to joint exercises between U.S. and South Korean forces.
"I think North Korea might decide it wants to talk if the U.S. and South Korea agreed to a temporary halt to those exercises, or even just to reduce their size and scope, but if not, I'm not optimistic," Wang said.
Meanwhile, Japan's defense ministry also highlighted "provocative acts" by China in the East China Sea and South China Sea as an area of concern.
The complaint comes after the foreign ministers of the 10-member Association of Southeast Asian Nations (ASEAN) indirectly criticized Beijing’s territorial expansion there in an unusual statement on Sunday.
In a reference to China’s building of artificial islands, air strips and other installations in the disputed waters, the ministers noted "concerns expressed by some ministers on the land reclamations and activities in the area, which have eroded trust and confidence, increased tensions and may undermine peace, security and stability in the region."
"We emphasized the importance of non-militarization and self-restraint in the conduct of all activities by claimants and all other states," the communique, which came as Beijing and ASEAN signed a code of conduct for the South China Sea, said.
Liou said Japan's comments were squarely aimed at ensuring a continued U.S. military presence in the region.
"When it comes to the South China Sea, of course Japan doesn't want to see a diminished U.S. presence," he said. "[They] don't want to see China become the dominant power in the Asia Pacific."
Reported by Gao Feng for RFA's Mandarin Service, and by Zhao Yan for the Cantonese Service. Translated and edited by Luisetta Mudie.