A quote from the White Paper:
"The MS-13 in El Salvador is significantly enhancing its weapons capacities,
transitioning away from a dependence on handguns via the acquisition of
automatic rifles such as AK-47s, along with grenades, rocket propelled
grenade launchers, and Light Anti-Tank Weapons.
Most of the weaponry is procured through theft or purchase from the
military, or from existing arsenals in Nicaragua. Some of the weapons are
passed on to TOCs, particularly the Mexicans, in exchange for cash and/or
small quantities of cocaine and crack that are sold in the local markets.
The gangs have taken advantage of government gun-buy-back programs to
turn in old and worthless weapons, using the income to buy higher quality
weapons in smaller quantities.
There are credible reports from multiple sources regarding MS-13
involvement in the protection and movement of SAM 7s from Nicaragua to a
clandestine arms market that operates in the Bajo Lempa region of El
Salvador, an area dominated by hardline former combatants of the
Communist Party faction of the FMLN during the war.
There have been important efforts, many of them successful, by Los Zetas to
recruit the best and most skilled MS-13 killers and gunmen, both in El
Salvador and Guatemala. Many of the recruits receive enhanced military
training in the Petén region of Guatemala and then operate either in
Guatemala or Mexico.. . "