Warfare on the North American frontier was brutal, and the killing of prisoners, the targeting of civilians, and other atrocities were widespread. In an incident that became well-known and frequently debated, British officers at Fort Pitt attempted to infect besieging Indians with blankets that had been exposed to smallpox. The ruthlessness of the conflict was a reflection of a growing racial divide between British colonists and American Indians. The British government sought to prevent further racial violence by issuing the Royal Proclamation of 1763, which created a boundary between colonists and Indians.