U.S. Secretary of State Hillary Clinton says North Korea's pursuit of nuclear weapons and ballistic missiles and ``pattern of provocations'' are a serious threat to Asian and world security.

North Korea released a statement later Thursday at the Association of Southeast Asian Nations' annual conference in Cambodia saying Washington's ``never-ending nuclear threat'' against the North has forced Pyongyang to build atomic weapons.

Animosity runs high after a North Korean rocket launch in April that Washington and Seoul call a cover for a banned long-range missile test. North Korea says it was a satellite launch attempt.

Clinton says Pyongyang's new leadership should focus on its people's ``needs and aspirations'' so it doesn't ``fall further behind.''

The North's statement says its nuclear program is a deterrent that reduces the risk of war. (AP)