U.S. Defense Secretary Robert Gates says there was no need to increase troop numbers in South Korea, after North Korea threatened an attack following its latest test of a nuclear bomb.
Speaking with reporters early Friday on a flight to Singapore, Gates says he is not aware of any unusual troop movements in North Korea.
Tensions have been running high on the Korean peninsula since the North tested an atomic bomb on Monday and then announced it would no longer be bound by the armistice that ended the Korean War in 1953.
On Thursday, South Korea said South Korean and U.S. troops raised their alert on the Korean peninsula to the highest level since 2006, when North Korea conducted its first nuclear test.
On Wednesday, North Korea said it would no longer be bound by the Korean War Armistice if the United States or South Korea interfered with its ships. The North Korean statement was a response to South Korea's decision to join a U.S.-led initiative that involves intercepting ships suspected of transporting weapons of mass destruction and related materials.
Representatives of the five permanent members of the United Nations Security Council met behind closed doors Thursday to weigh possible new sanctions against North Korea for its latest nuclear test.
Diplomats described the talks as constructive, but gave few details about what conclusions - if any - were made.
The United States and the four other permanent Council members, Britain, China, France and Russia, met with representatives from South Korea and Japan on Thursday to discuss a draft resolution that would condemn North Korea's nuclear test.
Diplomats say they are considering proposals for new sanctions, including expanding an arms embargo, and placing restrictions on financial and banking regulations.
Officials say it is not likely that a resolution will pass until next week.
Some information for this report was provided by AFP and AP.