North Korea was not mentioned, but it was apparent that Chinese President Xi Jinping was warning against possible provocative acts by the recalcitrant regime in the coming weeks.

In a joint news conference with his U.S. counterpart Barack Obama after their summit in Washington last week, Xi said China was committed to realizing the complete and verifiable denuclearization of the Korean Peninsula in peaceful way. This was a line that had long been repeated by Chinese officials.

But then Xi went a step further, saying China opposed any actions that might cause tension on the peninsula or “violate U.N. Security Council resolutions.” His remark was seen as a clear warning to Pyongyang not to push ahead with its threatened nuclear or missile tests, which are banned under a series of resolutions taken by the Security Council.

The North has recently suggested it may launch another long-range rocket and conduct a fourth nuclear test around the 70th founding anniversary of its ruling Workers’ Party.

Xi’s warning was highly unusual, given that Beijing has been reluctant to put pressure on Pyongyang in public and has customarily urged “all parties concerned” to be calm and exercise restraint in order to avoid escalating tensions.

Officials here may want to believe the strengthening relationship between South Korea and China prompted Xi to break out of Beijing’s repeated rhetoric. His unusual warning to the North could be in part an outcome from President Park Geun-hye’s attendance at a massive military parade in Beijing last month. Park’s decision to attend the event, which was shunned by Western leaders as being designed to demonstrate China’s military power, came at the risk of amplifying concern in the U.S. that Seoul was tilting too much toward Beijing.

It is also encouraging for South Korea that the Obama-Xi summit has put the two superpowers into a collaborative gear on denuclearizing the North.

A more immediate reason for the Chinese leader to have drawn a red line for Pyongyang may be that its additional provocations would result in pushing South Korea to consolidate trilateral security cooperation with the U.S. and Japan. Calls would be mounting in the South to introduce an advanced U.S. missile defense system, which China regards as a potential threat to its security.

North Korea conducted its third and latest nuclear test in early 2013, a few months after Xi took power. He is believed to have regarded the test, which followed a long-range rocket launch in defiance of Beijing’s request for restraint, as a personal affront to him.

In a reflection of his displeasure with the North, Xi became the first Chinese president to visit the South before the North. Xi, who traveled to Seoul in 2014, has yet to visit the North or meet with its young leader Kim Jong-un.

South Korea and China have enhanced their strategic partnership under the incumbent leaders, who held their sixth summit talks during Park’s trip to Beijing in September. Apparently buoyed by the outcome of her meeting with Xi, Park told reporters on the way home that South Korea and China would soon start in-depth consultations on the reunification of the peninsula.

It was unclear whether Xi’s unusual warning to the North signaled a fundamental shift in China’s perception of its intransigent neighbor as an increasingly burdensome, but strategically indispensable, buffer state. A key provider of food and fuel essential for the North’s survival, China has refrained from going as far as to inflict substantial damage on the impoverished regime for fear that the measure could lead to its collapse and the emergence of a pro-U.S. unified Korea.

Critics here may well have reasons to strike a cautious note against what they see as naive optimism held by Park and her aides about Seoul-Beijing ties and China’s support for the eventual unification of the peninsula.

True, a joint statement issued after the Park-Xi summit said the two leaders had “in-depth discussions on the reunification of the Korean Peninsula.” But China’s stance mentioned in the document that it supported the peaceful unification of the peninsula by the Korean people in a peaceful manner was little different from the phrase included in the agreement signed by the two countries in 1992 to set up formal diplomatic ties.

Park was not the only South Korean leader who seemed to have gone too far in gauging China’s intention regarding peninsular issues. Her predecessor, former president Lee Myung-bak, said in a series of interviews in the final days of his presidency that Seoul-Beijing relations were far better than portrayed in the media and that “serious dialogue” on the reunification of the peninsula had been underway between the two sides for about a year.

It may be a more realistic and safer assumption that China will never accept a reunified Korea that has a close security alliance with the U.S. As some experts note, China will not let the North Korean regime collapse, though it may not object to the ouster of its current unpredictable ruler if an alternative leadership could be installed.

More than ever, Seoul needs to read Beijing’s true intention and its ultimate strategy for handling peninsula issues. This will require cool heads, not wishful thinking, and a sophisticated approach shared by rival political camps and continued by future governments.

By Kim Kyung-ho

Kim Kyung-ho is an editorial writer for The Korea Herald. He can be reached at khkim@heraldcorp.com">khkim@heraldcorp.com. — Ed.