In its first major act of defiance since Senator Barack Obama’s election, North Korea said Wednesday that it would bar international nuclear inspectors from taking soil and nuclear waste samples, which are considered crucial to determining the extent of its weapons program.

The South Korean military has been placed on alert, according to media reports in the country, after a American satellite detected launch preparations for what appeared to be 10 short-range missiles at Chodo, a navy base.

North Korea has quietly built a long-range missile base that is larger and more capable than an older and well-known launch pad for intercontinental ballistic missiles, according to independent analysts relying on new satellite images of the site and other data.

The Bush administration for the first time says it has intelligence proving detailed and ongoing collaboration between Iran and North Korea in the development of new ballistic missiles. The Pentagon has also just released previously secret intelligence data on new Iranian and North Korean ballistic missiles under development.

While Iran and North Korea remain of the highest concern, the U.S. intelligence community is monitoring a number of additional states for signs of nuclear weapons programs, according to National Intelligence Director John Negroponte.

The United States has offered a detailed package of economic and energy assistance in exchange for North Korea’s giving up nuclear weapons and technology.

U.S. analysts believe that the technical problems that seemingly plagued the first North Korean nuclear test could be overcome in a matter of months.

North Korea's apparent test of a nuclear device could have a devastating effect on the world's long struggle to contain the spread of the most powerful military weapon known to man.

US military aircraft and monitoring centers scrambled yesterday to determine the size and type of the weapon that North Korea detonated in what is believed to be the reclusive regime's first test of a nuclear bomb.

U.S. Navy Adm. William J. Fallon, the admiral in charge of American forces in Asia, said that he believes North Korea has no missile capable of reaching long distances and is unlikely to have one "for a while."