Deputy Defense Secretary Paul Wolfowitz said Sunday that the prospect of terrorists developing nuclear capabilities is "more frightening and dangerous" than nuclear proliferation among nation states. 

At a regional security conference in Singapore, Wolfowitz said the concern that "nuclear weapons or scientists with nuclear expertise [could] fall into the hands of rogue regimes or terrorist groups is a very, very real one." 

"The events of Sept. 11 if anything ought to intensify our concerns about it," he said. 

Robert Einhorn, a former assistant secretary of state and a nuclear proliferation expert, said Southeast Asian ports in particular need to beef up security to help stem nuclear proliferation. 

"Governments should put in place strong shipment and transshipment controls to reduce the likelihood that their countries will become conduits for the ingredients of weapons of mass destruction programs worldwide," Einhorn said. 

The discussion on nuclear proliferation was one of a several seminars at a two-day conference, which was organized by the London-based International Institute for Strategic Studies and attended by more than 150 defense officials. 

Maj. Gen. Kim Kook-hun, head of the South Korean defense ministry's arms disarmament bureau, said his government is deeply concerned about North Korea's acquisition of weapons of mass destruction. 

President Bush has singled out North Korea as part of an "axis of evil" nations that sponsor terrorism or seek to develop weapons of mass destruction.