China sent a signal on the weekend that its leader Xi Jinping might meet North Korea’s young ruler Kim Jong-un later this year. In a news conference Sunday, Chinese Foreign Minister Wang Yi suggested they might hold their first meeting “when it is convenient for both parties.”

Kim, who took his hereditary power in 2011 following the sudden death of his father, has yet to make his debut on the international stage. Russia has said that Kim will attend a ceremony in Moscow in May to mark the 70th anniversary of the Soviet victory over Nazi Germany in World War II. Diplomatic observers see the possibility of Kim visiting China in September, when Beijing is scheduled to host its own event marking the end of the war.

Both occasions may set a “convenient” stage for a meeting between the leaders of China and North Korea.

Still, it was notable that Wang went the extra mile to emphasize the importance of ties between Beijing and Pyongyang. “The China-North Korea relationship has a strong foundation. It should not and will not be affected by temporary events,” he said.

China may feel the need to keep the North, which has been cold-shouldered by Beijing over its nuclear ambitions, from shaking off its influence by seeking to strengthen cooperation with Russia. But its signal of a possible summit between Xi and Kim came at a delicate time, when a knife attack by a pro-North Korean activist on the American ambassador to Seoul was strengthening South Koreans’ support for the alliance with the U.S. Some Saenuri Party officials responded by clamoring for the deployment of a U.S.-developed advanced missile defense system here, which has been opposed by China.

Pyongyang’s hailing of the bloody assault as a “deserved punishment and act of justice” has also exacerbated anti-North sentiment among the South Korean public, making it difficult for Seoul to push for dialogue with Pyongyang.

Under this changing atmosphere, Seoul’s diplomatic and security strategists could find it more challenging to strike a delicate balance between the U.S. and China while pushing to improve inter-Korean relations. They may need to recognize that South Korea cannot sit on the fence any longer on matters crucial to its security interests. Principled flexibility is what they should pursue in such increasingly volatile situations.