Gang violence became an increasingly difficult problem for El Salvador in the 1990s and early 2000s, in the wake of the country's civil war. During that war, hundreds of thousands of Salvadorans fled to the United States, many of them settling in Los Angeles. It was in southern California that the two largest Central American gangs, Mara Salvatrucha (MS-13) and Calle 18, were formed. After the end of the Salvadoran Civil War, the United States began deporting thousands of arrested gang members. This brought street gangs to El Salvador; the two gangs quickly became the largest criminal organizations in the country. The country's murder rate increased to 139 per 100,000 people in 1995, making El Salvador one of the most violent countries in the world.