Xi, speaking at an international conference in Boao, China, Sunday, made overt references to the tension on the Korean peninsula, wrought by saber-rattling out of Pyongyang.
"No one should be allowed to throw a region and even the whole world into chaos for selfish gain," Xi said. His government has officially called the unfolding crisis a "grave concern."
The New York Times said Xi and the Chinese, by far the reclusive North Korean regime's closest ally, are evolving in their approach to the ongoing war of words.
South Korean leaders have said they expect a military provocation from the North sometime this week and promised it would be met with harsh reprisals. In the past, the North has used such provocations to extract concessions in the form of economic and food aid from the United States and the world community.
"We see through their motive," said Kim Jang-soo, South Korea's director of national security. "Although North Korea shows no signs of attempting a full-scale war, it will suffer damage many times more than we do if it launches even a localized provocation.