Among Chinese officials, the mood toward the young North Korean leader, Kim Jong-un, has darkened. The Chinese government is reported by analysts to be wrestling with what to do about a man who, in power for a little more than a year, thumbed his nose at China by ignoring its appeals not to conduct the country’s third nuclear test, and who shows no gratitude for China’s largess as the main supplier of oil and food.

“The public does not want China to be the only friend of an evil regime, and we’re not even recognized by North Korea as a friend,” said Jin Qiangyi, director of the Center for North and South Korea Studies at Yanbian University in Yanji City. “For the first time the Chinese government has felt the pressure of public opinion not to be too friendly with North Korea.”…

If China decides to go along with the United States’ calls for much more stringent sanctions than exist now, there are fears among China’s policy makers that the North’s government would collapse, possibly setting the stage for mayhem on the border and a reunification of Korea as an American ally. But if China maintains the status quo, it could face mounting criticism among its own citizens.

If it decided to take a harder stance, China could punish North Korea by curtailing its oil shipments, by far the major source of fuel in the energy-starved North, Mr. Jin said.