The president said he planned to speak by telephone Friday night with Chinese President Xi Jinping.
China has indicated that it would stay neutral if North Korea struck first and the United States retaliated but would intervene on behalf of Pyongyang after a U.S. first strike.
In other world reactions Friday, German Chancellor Angela Merkel said that “verbal escalation” was the “wrong response” to Pyongyang’s heated rhetoric, and Russian Foreign Minister Sergei Lavrov said his country was equally worried about U.S. talk of a preemptive strike and North Korea’s warning of an attack near Guam.