The excavation at North Korea's northeast Punggye-ri site, where nuclear tests were conducted in 2006 and 2009, is in its final stages, according to a report by intelligence officials that was shared Monday with The Associated Press.
Its release comes as North Korea prepares to launch a long-range rocket that Washington and others say is a cover for testing missile technology that could be used to fire on the United States.
Observers fear a repeat of 2009, when international criticism of the North's last long-range rocket launch prompted Pyongyang to walk away from nuclear disarmament negotiations and, weeks later, conduct its second nuclear test. A year later, 50 South Korean were killed in attacks blamed on the North.
"North Korea is covertly preparing for a third nuclear test, which would be another grave provocation," said the report, which cited
U.S. commercial satellite photos taken April 1