Sureños, Sur 13, or Sureñas for females, are groups of loosely affiliated gangs that pay tribute to the Mexican Mafia while in U.S. state and federal correctional facilities. Many Sureño gangs have rivalries with one another and the only time this rivalry is set aside is when they enter the prison system. Thus, fighting is common among different Sureño gangs even though they share the same common identity. Sureños have emerged as a national gang in the United States. They would ally themselves with the Crips and MS13 in certain U.S. states. Sureños have been documented in the U.S. military, found in both U.S. and overseas bases.