China’s president, Xi Jinping, said Sunday that no country should be allowed to threaten world peace. “No one should be allowed to throw a region and even the whole world into chaos for selfish gain,” said Mr. Xi in his first pointed comment on the Korean crisis. He did not name any country, but separately, China’s Foreign Ministry Sunday spoke of its “grave concern” over the rising tensions on the Korean Peninsula. The Chinese comments came after Washington said Beijing faces a choice between reining in North Korea or facing a larger American military presence in East Asia.