World War II was seen as a significant success for chemical arms control as none of the belligerents made significant use of chemical weapons. In the immediate aftermath of the war, arms control efforts focused primarily on nuclear weapons given their immense destructive power, and chemical disarmament was not a priority. Nonetheless, chemical warfare began to expand again with gas attacks during the Yemeni Civil War, and allegations of use during the Korean War. Along with the substantial use of chemical weapons in the Iran–Iraq War, these incidents led to a renewed interest in chemical disarmament and increased the push towards disarmament, finally culminating in the 1993 Chemical Weapons Convention, a full-scale ban on the use, production and stockpiling of weapons, which took force in 1997.