North Korea may be preparing to test another long-range missile designed to fly as far as the United States.
South Korea's Yonhap news agency Monday quoted an intelligence official in Seoul as saying that the North has moved a long-range ballistic missile to a west coast launch site in preparation for a possible test launch.
A U.S. delegation led by Deputy Secretary of State James Steinberg is in Asia for talks on how to respond to North Korea's second nuclear test, which took place on May 25. Steinberg met with Japanese Foreign Minister Hirofumi Nakasone Monday in Tokyo. The two called for additional U.N. sanctions against Pyongyang.
But North Korea remains defiant and has threatened to take unspecified "self-defense" action if new international sanctions are imposed.
In Washington, White House spokesman Robert Gibbs said the Obama administration's biggest concern is the possibility that North Korea may give nuclear weapons to others.
Also Monday, the U.S. ambassador to the United Nations, Susan Rice, reported progress in drafting what she called "a very worthy and strong resolution" on tougher sanctions against North Korea.
Adding to tensions, the North has scheduled for Thursday the trial of two U.S. journalists it detained in March. Pyongyang is charging them with illegal entry into North Korea and unspecified "hostile acts."
Meanwhile, South Korean President Lee Myung-bak and leaders of the Association of Southeast Asian Nations called on North Korea to give up its nuclear ambitions and respect U.N. sanctions.
The leaders made the call Monday at a special two-day summit on the South Korean resort island of Jeju to mark 20 years of partnership between Seoul and ASEAN.
The six-nation talks aimed at getting Pyongyang to dismantle its nuclear program in exchange for aid and energy stalled after the last meeting in December in China. The United States, Russia, China, South Korea and Japan are parties to the talks with the communist regime.
Some information for this report was provided by AFP, AP and Reuters.