The White House, responding to a US media report that North Korea may be preparing for an underground test of a nuclear bomb, said such a test would be an "extremely provocative" act that would be denounced around the globe.
ABC News on Thursday quoted an unidentified senior US State Department official as saying, "It is the view of the intelligence community that a test is a real possibility."
ABC also quoted an unidentified senior military official as saying that a US intelligence agency recently had observed "suspicious vehicle movement" at a suspected North Korean test site. The activity involved the unloading of reels of cable outside an underground facility in northeast North Korea.
White House officials declined to confirm the report.