South Korean President Park Geun-hye said the North has been "carrying out a reign of terror", after news of the purge of Chang Song-thaek.
"We hope North Korea can maintain national stability, the people's well-being and economic growth. China will remain committed to developing the friendly relationship between China and North Korea," China's Foreign Ministry spokesman Hong Lei said.
North Korea confirmed on Monday that Mr Chang had been stripped from his official posts.
"The party eliminated Jang [Chang] and decisively purged his group, dealing a telling blow at its dangerous factional acts," state news agency KCNA said.