New Activity at North Korean Nuke Test Site

SEOUL, South Korea — North Korea has renewed activity at suspected nuclear test sites, including the movement of people, vehicles and material, U.S. intelligence sources said.

Officials said the activity, which has been observed by intelligence agencies for several weeks, does not indicate that a test is imminent, but does increase the likelihood of a nuclear test.

"At some point, you would think they would test it if they truly think they have the capability," one official said.

A test could be carried out without much forewarning, another official warned, adding that a decision to conduct a test by the closed society would only be done with political ramifications in mind.

The new intelligence comes as Asian nations scrambled to forge a common front against Pyongyang's threatened nuclear test, with South Korea warning of a regional atomic arms race that could upend the balance of power in Northeast Asia.

Diplomatic maneuvering kicked into high gear, as Japan, China and South Korea announced a series of summit meetings over the next week to repair damaged ties and coordinate a strategy on North Korea despite no signs of an imminent test.