Last week, a North Korean flag appeared during the largest US-South Korea military drills since the Korean War; now Pyongyang is taking the countries to task. "It is an extremely grave military action and politically-motivated provocation to fire live bullets and shells at the flag of a sovereign state without a declaration of war," the North said in a statement. Pyongyang "will further bolster up its nuclear deterrent for self-defense as long as the US ... persists in its hostile policy." The flag wasn't actually hit in the drills, which the South has labeled a warning to the North, the AP notes. (More North Korea stories.)