SEOUL, South Korea — North Korea says it has conducted a hydrogen bomb test. The surprise announcement that complicates already difficult efforts to curb the country's push for a working nuclear ...

The White House says the U.S. government's early analysis of underground activity in North Korea "is not consistent" with that country's claim of having conducted a successful hydrogen bomb test.

"Such actions are fraught with further aggravation of the situation on the Korean peninsula, which is anyway marked by very high potential of military and political confrontation," said the ministry's ...