North Korea says it will have a fully developed plan for striking Guam with intermediate-range missiles by mid-August.
A state media report suggests the US territory could be attacked by four missiles.
US President Donald Trump has responded to the threats, warning North Korea the US nuclear arsenal is more powerful than ever.
It comes as the US secretary of state Rex Tillerson landed on the island of Guam, saying Americans can feel safe because there is no imminent threat from North Korea.

