Hydrogen bomb

North Korean official says H. bomb possible in Pacific

Ri Yong Ho was speaking in New York to reporters from South Korea's Yonhap news agency who asked him to clarify a threat made by his leader against the United States.

Kim Jong-un had warned of the "highest level of hard-line countermeasure in history."

Mr Ri said North Korea could consider a hydrogen bomb test, although he qualified this by saying he did not know Kim's exact thoughts.

Photo: STF / AFP A file photo from July 2014 shows an atomic bomb explosion in Bikini Atoll. 

North Korea nuclear test: UN vows new measures

The council condemned the test, saying "a clear threat to international peace and security continues to exist".

This is the North's fourth nuclear test since 2006, but if confirmed would be the first of an H-bomb.

However, the US has joined nuclear experts in questioning whether the blast was large enough for such a test.

US White House spokesman Josh Earnest said "initial analysis was not consistent with North Korea's claims of a successful hydrogen bomb test".