The rare public spat between China and North Korea illustrates the dilemma facing Beijing's leaders as they try to coax Kim Jong Un back to the negotiating table.

North Korea condemned China for banning coal imports in an unusually hostile state-media commentary last week, mocking its ally for "dancing to the tune of the U.S." and vowing to continue developing nuclear weapons. China stood firm, saying it would implement United Nations Security Council resolutions.

"Does anyone truly believe that the Korean nuclear issue is an easy one to solve, considering it has been with us for these many years?" Chinese Ministry of Foreign Affairs spokesman Geng Shuang asked reporters Friday. The two nations remained "friendly neighbors," he added.