Mullen spoke to the Financial Times in Brussels where he was attending a meeting of NATO military heads.
Citing his recent talks with Chinese officials and last week's summit between U.S. President Barack Obama and his Chinese counterpart, Hu Jintao, Mullen said Beijing is serious about its responsibilities relating to North Korea, the Times said in an article published Thursday. In this context, Mullen also mentioned U.S. Defense Secretary Robert Gates's visit to China prior to the Washington summit.
"The recent dialogue has been very open about what, first of all, the concerns are, and secondly ... the recognition of the responsibilities that the big powers have," Mullen was quoted as telling the Times.
"There really is a commitment, from my perspective, on the part of the leaders to contain this thing and to get to a point where serious deterrents, both actions and options, are there."
North Korea's recent actions have raised tensions on the Korean Peninsula. Those actions have included its shelling of a South Korean border island that killed four people and the sinking of a South Korean war ship last March that Seoul blames on Pyongyang. The North also has conducted two nuclear tests and is reported to be involved in uranium enrichment.
China is the closest friend of North Korea and Mullen said it is the only nation that can influence the repressive Communist country.
"We all agree it's a more dangerous place now than it was a few months ago," Mullen said. "I'm a little more comfortable that everybody recognizes the seriousness of the problem."