Establishment of the Sisa Valley detachment
In 1987, the MRTA established the Valle del Sisa detachment under the command of Carlos Arango, with an area of influence in the provinces of El Dorado and Saposoa. This area was considered strategic because it was an access point to other important areas in the department of San Martin.
In 1987, the MRTA established the Valle del Sisa military detachment, commanded by Carlos Arango, as part of its organizational structure in the Northeastern Front. This area was considered strategic by the MRTA because it was an access point to the Alto Mayo, Middle Mayo, Huayabamba Valley and Central Huallaga. The detachment's area of influence was the province of El Dorado and the province of Saposoa. This detachment was part of the eight zones controlled by MRTA in the department of San Martin, each with its own military detachment and command structure.