Massive aerial bombardment against Pathet Lao and invading NVA communist forces was carried out by the United States to prevent the collapse of Laos' central government, the Royal Kingdom of Laos, and to prevent the use of the Ho Chi Minh Trail to attack U.S. forces in South Vietnam and the Republic of Vietnam. As of 2008, Laos is the most heavily bombed country, per capita, in the world. An average of one B-52 bomb-load was dropped on Laos every eight minutes, 24 hours a day, between 1964 and 1973. Due to the particularly heavily impact of cluster bombs during this war, Laos was a strong advocate of the Convention on Cluster Munitions to ban the weapons and assist victims, and hosted the First Meeting of States Parties to the convention in November 2010.