Strong explosion in North Korea unlikely nuclear–US

SEOUL—A large explosion rocked North Korea’s northern inland province of Ryanggang last week, South Korea’s Yonhap news agency said Sunday, although US officials are “pretty sure” the blast was not a nuclear explosion or test but there is no definitive explanation yet, a State Department official said on Saturday.

The explosion appeared to be stronger than an April 22 blast that killed more than 150 people and wounded some 1,300 others in Ryongchon near the western tip of North Korea’s border with China, it said.