Increasing violence perpetrated by drug trafficking organizations (DTOs) and other criminal groups is threatening citizen security in Mexico and Central America. Drug-related violence claimed more than 5,600 lives in Mexico in 2008, and several Central American countries have among the highest homicide rates in the world. Mexican DTOs dominate the illicit drug market in the United States and are expanding their operations by forming partnerships with U.S. gangs. As a result, some of the drug-related violence in Mexico has spilled over into the United States.