North Korea Has Built Underground Tunnel, Possible Sign For Nuclear Test

North Korea has built an underground tunnel for possible use in a nuclear test, a South Korean newspaper reported, amid concerns that the communist nation may be planning such a move.A 700-meter-deep (2,300-foot-deep) shaft has been built with a horizontal tunnel running nearby at Mount Mantap in North Hamkyong province on the North's northeast coast, the English-language JoongAng Daily reported, citing Chung Hyung-keun, a lawmaker from the opposition Grand National Party. Chung obtained the information from the National Intelligence Service, the South's spy agency, according to the report.