MS-13 becomes Trump's public enemy No. 1

With as many as 10,000 members in 46 states, MS-13 has diversified its operations from a violent street gang, with members being convicted of crimes ranging from kidnapping and murder to drug smuggling and human trafficking. (REUTERS/Ulises Rodriguez)

MS-13, or Mara Salvatrucha, was founded more than two decades ago in Southern California by immigrants fleeing El Salvador's civil war. Its founders took lessons learned from the brutal conflict to the streets of Los Angeles, as they built a reputation as one of the most ruthless and sophisticated street gangs in the country.  (REUTERS/Ulises Rodriguez)

They have since spread throughout their home nation and helped El Salvador become the country with the fourth highest per capita murder rate in the world, according to the United Nations Office on Drugs and Crime. A large wave of Salvadorans entering the U.S. in recent decades has helped the gang spread from their roots in Los Angeles and El Salvador to many immigrant pockets of the U.S. (REUTERS/Jose Cabezas)

The Trump administration has made the group a focal point in the national immigration debate, although it is in some respects a homegrown organization and it is unclear how many of its members are in the U.S. illegally. (AP Photo/Alex Brandon)

Trump has said aggressive immigration enforcement is the answer to MS-13, and the administration already is boasting of success. Federal authorities have announced the arrests of hundreds of suspected MS-13 gang members in recent months, but Trump’s claim of getting rid of MS-13 members "by the thousands" may be an exaggeration. (AP Photo/Frank Franklin II)

Attorney General Jeff Sessions traveled to El Salvador last week to learn more about how the gang's activities in the Central American nation affect crime in the U.S. Officials believe major gang leaders are using cellphones from Salvadoran prisons to instruct members who have crossed into the U.S. illegally to kill rivals and extort immigrants. (REUTERS/Jose Cabezas)