America\'s top military officer on Sunday urged China to use its relationship with Pyongyang to ensure regional stability, while warning North Korea against further provocations. Admiral Mike Mullen, chairman of the US Joint Chiefs of Staff, stressed the US would remain active in the Asia Pacific region for a long time, but insisted Washington was in no way seeking to contain China\'s dramatic rise. \"North Korea and the leadership of North Korea is only predictable in one sense and that is -- if you base it historically -- they will continue to provocate,\" Mullen told reporters after arriving in Beijing. \"The provocations I think now are potentially more dangerous than they have been in the past.\" Tensions in Northeast Asia have risen sharply since South Korea accused the North of torpedoing a warship in March 2010, killing 46 sailors. Pyongyang angrily denied the charge but went on to shell a border island in November, killing four South Koreans including two civilians. Six-party nuclear disarmament talks, grouping the two Koreas, China, Japan, Russia and the United States, have been stalled since the North abandoned them in April 2009. It staged its second nuclear test a month later. \"All of us are focused on a stable outcome here of what is increasingly a difficult challenge with respect to the leadership in North Korea and what it might do,\" Mullen said. \"The Chinese leadership, they have a strong relationship with the leadership in Pyongyang and they exercise that routinely ... continuing to do that as they have done in the past is really important.\" On a four-day trip to China, Mullen said he would discuss that and other issues in talks with his counterpart General Chen Bingde and while visiting military bases as the two nations seek to bolster their security cooperation. The trip coincided with a joint naval exercise that began Saturday with the US, Japanese and Australian navies in the South China Sea, where recent Chinese assertiveness over territorial claims has raised tensions. \"China and the United States are both Pacific powers and will be for a long, long time ... I can\'t think of a place where there is more to be done and more to be gained than between the United States and China,\" Mullen said. \"This region and the global challenges that we face together are just too vital and too vast for us to continue to find obstacles to a better understanding of each other,\" Mullen said. During his trip, the first to China by a US chairman of the joint chiefs since 2007, Mullen said he would also discuss the Taiwan issue, stability in the South China Sea and confidence-building measures between the two nations. \"Containing China is not the case ... we would like to see China in the long run to be a strong partner with the United States to resolve some of the issues that we have got both regionally and globally,\" Mullen said.