URGENT ¥¥¥ N.Korea nuclear strike only if survival threatened: US

North Korea would likely only use nuclear weapons if it perceived a threat to its survival, but the United States remains uncertain how it would define such a threat, the US national intelligence chief said Tuesday.

"Although we assess with low confidence that the North would only attempt to use nuclear weapons against US forces or allies to preserve the Kim (Jong-Un) regime, we do not know what would constitute, from the North's perspective, crossing that threshold," James Clapper, director of national intelligence, said in an annual report to Congress on global security threats.