South Korean protesters stage a rally in Seoul Monday to oppose the possible deployment of the United States’ advanced defense system THAAD on the Korean peninsula. (Ahn Young-Joon/AP)

— The threat of an American missile defense system being stationed in South Korea appears to have concentrated minds in Beijing on how to punish Pyongyang.

China now seems ready to support limited United Nations sanctions against North Korea over a recent nuclear test and rocket launches, partly in response to U.S. pressure, experts said Monday.

Beijing has reacted angrily to the prospect of the Terminal High Altitude Area Defense (THAAD) system being deployed in South Korea, but a tougher line from Washington and Seoul seems to be having some effect on Beijing's calculations, experts said. At the very least, Beijing is now talking up the prospect of stiffer sanctions against North Korea.

In an editorial on Monday, China Daily argued that the missile defense system was not the answer to the North Korean crisis.

“There will be no ground for its introduction should the parties agree to a sanctions package that is sufficient for Pyongyang to reevaluate its nuclear program,” the editorial said. “For that to happen, the new U.N. resolution must truly bite.”

The editorial echoes comments by Foreign Minister Wang Yi, who told Reuters in Munich on Friday that the United Nations should adopt a resolution to ensure “North Korea will pay the necessary price and to show there is a consequence for its behavior.”

China, of course, would never admit it was reacting to American pressure. It still favors much weaker sanctions than those proposed by the United States and is likely locked in negotiations to “soften the blow,” according to Yanmei Xie, a senior China analyst at the International Crisis Group in Beijing.

It could even be argued that Beijing is merely hyping the likely effect of a limited sanctions package to convince Seoul that the anti-missile system deployment is unnecessary — and to cast Washington as the real troublemaker.

Still, even nationalist tabloid Global Times argued Monday that China should shift policy toward North Korea in the face of “mounting pressure and growing challenges.”

It argued that elite and public opinion was changing, with greater numbers of people now seeing North Korea as a “burden and an annoying neighbor rather than an old friend.” This in turn led to a shift in favor of actions that “make Pyongyang feel pain for its obduracy.”

“The more China’s policy in this regard departs from public opinion, the more political cost China has to pay,” the Global Times wrote.

After North Korea launched a rocket this month, apparently to test its ballistic missile technology, Seoul agreed to begin talks with Washington on deploying a THAAD unit with the U.S. military in South Korea.

THAAD is a land-based system designed to shoot down incoming short-, medium- and intermediate-range missiles, and could offer South Korea and some of the 25,000 U.S. troops deployed there greater protection against missiles launched from the North.

The threat of deployment comes amid growing frustration in both Seoul and Washington not only with Pyongyang’s actions but also with China’s muted response.

But some Chinese experts argue the THAAD system is mainly used for intercepting long-range missiles rather than short-range ones, and that its real target is China. They argue that the proposal has undermined Beijing’s friendship with Seoul and widened distrust with the United States.

Foreign Ministry spokesman Hong Lei said Monday that the missile defense system would “directly violate” China’s strategic security interests, and he condemned “relevant countries” for using the Korea peninsula issue to undermine those interests.

“There is still a huge gulf separating China and the United States in terms of their strategic goals over the North Korea issue,” said Shi Yinhong, director of the Center for American Studies at Renmin University of China in Beijing.

He said China was willing to speed up U.S. Security Council negotiations but would not agree to any sanctions that covered its own trade with North Korea or affected its neighbor’s access to food or oil.

Any sanctions, he said, would be less tough than measures China itself adopted in 2013, shortly after President Xi Jinping took power and at a time when relations with Washington were on an upswing.

“Now it is impossible for China to do the same thing, given the state of Sino-U.S relations,” he said. “Also, if China sanctions North Korea like it did in 2013, North Korea will become more of an enemy.”

The Crisis Group’s Xie said China probably aims to do just enough in terms of sanctions to placate the South Korean government and convince Seoul to again drag its feet over the THAAD deployment, as it has done for years.

“China may agree to narrow sanctions targeting certain individuals and entities but not those that could remotely threaten to destabilize the country or regime, or turn North Korea into an openly hostile neighbor,” she said.

Sanctions of that nature might dial up the pressure on the North Korean regime a notch but are very unlikely to persuade it to abandon a nuclear program that has become a cornerstone of the regime’s national security calculations, experts said.

Gu Jinglu contributed to this report.