Later, the Sioux were defeated in a series of subsequent battles by the reinforced U.S. Army who continued attacking even in the winter, and most were forced to move onto reservations, mostly outside of Montana, primarily by tactics such as preventing buffalo hunts and enforcing government food-distribution policies to friendlies only. The Lakota were compelled to sign a treaty in 1877 ceding the Black Hills to the United States, but a low-intensity war continued, culminating, fourteen years later, in the killing of Sitting Bull (December 15, 1890) at Standing Rock and the Wounded Knee Massacre (December 29, 1890) at Pine Ridge.