"The North will only be able to stabilize its regime, maintain peace and achieve economic prosperity when it gives up its nuclear program," the Yonhap news agency quoted the new South Korean leader as saying at a policy briefing.

In Washington, Christopher Hill, chief U.S. negotiator on the North's denuclearization effort, said the Communist country has said it wants to complete its task before U.S. President George Bush leaves office in January 2009, Kyodo news service reported.

The denuclearization talks among the United States, Russia, China, Japan and the two Koreas are stalled because North Korea has yet to give a full description of its nuclear facilities that would be acceptable to the other members.

"We should pick up the pace," Hill was quoted as saying, adding if the North gives up nuclear weapons and rejoins the Nuclear Non-Proliferation Treaty, the incentives would include full diplomatic ties with the United States and a civilian nuclear program with other members.

Lee said the North's leadership must realize settling the issue will also help inter-Korean economic cooperation, Yonhap reported.