Not states but territories, Guam, the Philippines and the Hawaiian Islands. But the violations of international law were cities in China for the Japanese, Guernica, Warsaw and other Polish and French cities as well as London and numerous other British cities for the Germans. They were allies of the USA.
The casualties in Hiroshima and Nagasaki were lower than in the other Japanese cities that were firebombed to rubble. Both were military targets, not civilian ones. Hiroshima was a major naval base and shipyard that was busily turning out suicide subs and boats, Nagasaki was a regional army headquarters and production facility.