The highest-ranking U.S. military officer urged China on Thursday to do more to prevent North Korea from taking provocative actions.

Holding a news conference at the U.S. Embassy in Tokyo, Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, harshly condemned Pyongyang for its recent belligerence against Seoul and the disclosure of a new uranium enrichment facility.

Much of the volatility in the world today "is owed to the reckless behavior of the North Korean regime enabled by their friends in China," Mullen said. Pyongyang's "utter refusal to make informed, mature decisions on behalf of their own people defies both logic and human compassion."