Kim's visit to China is his latest move in an increasingly assertive foreign policy as he seeks to align Pyongyang with Beijing and Moscow in a united front against the United States under what he portrays as a "new Cold War." It's his first visit in a year.

The U.S. Treasury Department proposed a rule Thursday to crack down on American high-tech investments such as supercomputing and artificial intelligence in China, Russia, North Korea and other "countries of concern."