The nominee for U.S. assistant secretary of defense for Asian and Pacific security affairs says North Korea’s missile and weapons of mass destruction programs (WMD) pose a “direct and serious threat” to U.S. territory as well as U.S. allies.

Mark Lippert made the remark on Thursday in a written reply to policy questions by the Senate Armed Services Committee at a confirmation hearing.

Lippert said the North’s uncertain prospects over power succession and obscurity of the North’s communist regime are further raising concerns over its nuclear and WMD programs.

He also said that issues regarding the North cannot be resolved with deterrence alone, and he stressed the need for diplomacy as well in dealing with Pyongyang.

When asked how the U.S.-North Korea joint excavation of remains of U.S. soldiers from the Korean War will affect the six-way nuclear talks, Lippert said the matter is a humanitarian issue that is separate from other political issues.