North Korean Minister of Foreign Affairs Ri Yong Ho said that his country may consider a test of a hydrogen bomb in the Pacific Ocean, according to a report from South Korea's official news agency Yonhap.
Ri said the potential test of "the most powerful detonation of an H-bomb" would be one possible "highest-level" action against the U.S., according to the report.
He added that he didn't know what actions would be ordered by Kim Jong-un, Yonhap reported.
Ri's threat is significant because such a detonation would move North Korea's nuclear weapons activities beyond its borders for the first time. Japan, for example, lies between North Korea and the Pacific Ocean.
The communist dictatorship's previous nuclear tests have taken place in its isolated mountains.