The U.S. is putting regional stability in East Asia at risk, a Chinese spokesman said Saturday following remarks by President Donald Trump's defense secretary that a U.S. commitment to defend Japanese territory applies to an island group that China claims.

Chinese Foreign Ministry spokesman Lu Kang on Saturday called on the U.S. to avoid discussion of the issue and reasserted China's claim of sovereignty over the tiny uninhabited islands, known in Japanese as the Senkaku and Chinese as Diaoyu.