On the afternoon of December 10, 1981, units of the Salvadoran army's Atlacatl Battalion, which was created in 1980 at the U.S. Army's School of the Americas, arrived at the remote village of el Mozote after a clash with guerrillas in the vicinity. The Atlacatl was a "Rapid Deployment Infantry Battalion" specially trained for counter-insurgency warfare. It was the first unit of its kind in the Salvadoran armed forces and was trained by United States military advisors. Its mission, "Operación Rescate" ("Operation Rescue"), was to eliminate the rebel presence in a small region of northern Morazán where the FMLN had two camps and a training center.