SUMMARY

The rivalry between M18 and MS-13 had its roots in the United States, where both gangs were formed by Salvadoran immigrants fleeing the civil war in their home country during the 1980s. Over time, the gangs grew in size and influence, and following mass deportations, both established a strong presence in Central America.

While low-level violence between the two groups was a near-constant feature of their rivalry, with killings occurring on a regular basis, large-scale clashes erupted periodically, often triggered by shifts in gang leadership that prompted internal restructuring and renewed competition over territorial boundaries.

Neither gang issued formal public statements justifying violence against the other, though the territorial logic of their conflict was well-documented. Control over territory was treated as an operational necessity, with dominance over neighborhoods and regions being central to both gangs' criminal activities, including extortion and drug trafficking. Thus, attacks on rivals were understood within both organizations as an instrument of expansion and deterrence.

Both gangs employed similar tactics, including executions, drive-by shootings, and attacks with firearms and hand grenades. Violence was particularly acute within prison settings, where clashes erupted despite informal truces. For example, in August 2005, fighting broke out in several detention facilities across Guatemala, in violation of an existing agreement between the gangs not to attack each other in prison.

The conflict was not confined to a single country, for both gangs maintained a strong presence in Guatemala, El Salvador, Honduras and the United States, while their activities were also reported in Mexico.

The non-state conflict between M18 and MS-13 is first included in UCDP data in 2005. In August of that year violent clashes in different prisons in Guatemala resulted in over 25 deaths.