South Korea ? U.S. Defense Secretary Robert Gates said today that North Korea continues to pose a grave threat to international peace and pledged to maintain a nuclear deterrent in the region.

Gates and his South Korean counterpart, Kim Tae-young, said their two nations would never accept North Korea as a nuclear weapons state. They accused the regime of undermining global security with atomic and missile threats, and said recent overtures from Pyongyang do not diminish the serious atomic threat.

Ballistic missile and nuclear weapons tests conducted in April and May “clearly violate” U.N. Security Council resolutions and international disarmament agreements, they said in a joint statement following their talks.

The violations “undermine the global nonproliferation regime and constitute direct and grave threats to peace and stability” not only for South Korea and the region but also for the broader international community, they said.