The Chinese Foreign Ministry also spoke about Mattis' visit. Our reporter Sun Ye has more.

SPOKESPERSON CHINESE FOREIGN MINISTRY "Recently, as we can see, China and the US have achieved some progress in military exchanges. It is normal for differences to emerge from time to time between two big countries. The important thing is, that whenever these problems may rise, both sides should be able to properly handle such differences in the spirit of mutual respect and mutual understanding -- broadening cooperation and managing differences. We believe that relations between China and the US can benefit both countries and their people."