North Korea has tested multiple intercontinental ballistic missiles (ICBM) since 2017, each time launching them on lofted trajectories that extend far above the Earth in an apparent attempt to avoid overflying other countries.

But Pyongyang has signaled that it may soon flatten out these flight paths as part of full-range tests — potentially sending missiles closer than ever to U.S. territory. The leader’s powerful sister Kim Yo Jong, for instance, has threatened to use the Pacific Ocean as a “firing range,” while calling any U.S. efforts to intercept these missiles a “declaration of war.”