Despite the reforms, virtually all Dominicans resented the loss of their sovereignty to foreigners, few of whom spoke Spanish or displayed much real concern for the nation's welfare, and the military government, unable to win the backing of any prominent Dominican political leaders, imposed strict censorship laws and imprisoned critics of the occupation. In 1920, U.S. authorities enacted a Land Registration Act, which broke up the "terrenos comuneros" and dispossessed thousands of peasants who lacked formal titles to the lands they occupied, while legalizing false titles held by the sugar companies. In the southeast, dispossessed peasants formed armed bands, called "gavilleros", waging a guerrilla war that lasted six years, with most of the fighting in Hato Mayor and El Seibo. At any given time, the Marines faced eight to twelve such bands each composed of several hundred followers. The guerrillas benefited from a superior knowledge of the terrain and the support of the local population, and the Marines relied on increasingly brutal counterinsurgency methods. However, rivalries between various gavilleros often led them to fight against one another, and even cooperate with occupation authorities. In addition, cultural schisms between the "campesinos" (i.e. rural people, or peasants) and city dwellers prevented the guerrillas from cooperating with the urban middle-class nationalist movement.