BOGOTA (AP) — New militias have arisen to replace Colombia's notorious right-wing paramilitary groups and they are committing the same sorts of violence as their predecessors, a prominent international rights organization said Wednesday.

More than 31,000 fighters have been demobilized from the paramilitary coalition known as the United Self-Defense Forces of Colombia, or AUC, in recent years, but dozens of newly emerged successor groups have engaged in activities ranging from mass murder to extortion, according to New York-based Human Rights Watch.

The paramilitaries were organized by rural landowners seeking protection from leftist rebels, but they soon became a powerful, lawless drug-dealing force in much of the country. The U.S. government has declared the AUC a terrorist organization.

Government pressure led the paramilitaries to disband between 2003 and 2006.