Damage to Fourth Infantry Brigade compound from guerrilla attack, El Paraíso, Chalatenango Department, December 1983
Courtesy United States Department of Defense

Although the FMLN continued to suffer from long-standing sectarian rivalries, the FMLN groups--with Cuban training and other assistance--reorganized during 1983. The FMLN divided the country into five war fronts: the Feliciano Amo Western Front (covering Ahuachapan, La Libertad, Santa Ana, and Sonsonate departments), Modesto Ramirez Central Front (including Cuscatlan, San Salvador, and parts of Cabanas and La Paz departments), Anastasio Aquino Paracentral Front (comprising parts of Cabanas and La Paz departments, as well as San Vicente Department), Francisco Sanchez Eastern Front (covering La Union, Morazan, San Miguel, and Usulutan departments), and Apolinario Serrano Northern Front (consisting of Chalatenango Department).

The individual FMLN groups each claimed traditional areas of operation and influence within the five FMLN fronts and were organized on Marxist-Leninist structures. The ERP, which had a Marxist-Leninist political front, the Party of the Salvadoran Revolution (Partido de la Revolucion Salvadorena--PRS), was a particularly well-organized group. Directed by its nine-member general command, the ERP's principal force was the Rafael Arce Zablah Brigade (Brigada Rafael Arce Zablah--BRAZ), which operated on the Francisco Sanchez Eastern Front. The BRAZ was subdivided into two groups consisting of several battalions. The FPL operated on the northern, central, and western fronts. Directed by a general command, composed of more than twenty-five commanders, the FPL's leadership structure also included a revolutionary council, a central committee, and a political commission. The FPL's complex military structure was also collectively known as the Popular Army of Liberation (Ejercito Popular de Liberacion--EPL). Virtually indistinguishable from the FPL, the EPL was composed of elite "vanguard units," less skilled "guerrilla columns," and the "urban front" commando groups in the cities.

Based primarily in the area of Guazapa Volcano, the FARN served as the military apparatus of the National Resistance (Resistencia Nacional--RN) party, a Marxist-Leninist political front whose secretary general and second in command constituted the FARN's general military command. The PRTC operated with other FMLN groups through its armed wing, the Revolutionary Armed Forces of Popular Liberation (Fuerzas Armadas Revolucionarias de Liberacion Popular--FARLP). In addition to its rural forces, the PRTC had a San Salvador-based terrorist apparatus called the Mardoqueo Cruz Urban Guerrilla Commando. The PCES military wing, the FAL, also reportedly was based at Guazapa Volcano, but its principal rural guerrilla force operated mainly in northern and central El Salvador. Although Handal commanded the FAL, it also had an operational commander.

In the late 1980s, the rebels were still operating in small units, 931 , avoiding confrontations with the army except on their own terms, and emphasizing hit-and-run attacks mainly against economic targets. In 1986 FMLN attacks on the economy increased by 29 percent. The eastern region of El Salvador, the FMLN's main area of operations, suffered the brunt of the sabotage campaign. The FMLN facilitated its operations in El Salvador by using as sanctuaries demilitarized border zones (bolsones), such as north of the Torola-Jocoaitique line in northern Morazan Department.

One of the FMLN's prime objectives was to sabotage the country's economic infrastructure by attacking systematically such targets as bridges, the power grid, and communications equipment. Guerrilla forces also disrupted the transportation system by paralyzing road traffic every month or two. The intimidation of private investors through threats, "war taxes," kidnapping, and armed attacks on their business premises was another aspect of this strategy, as was the infiltration of labor unions in an effort to promote unrest. Guerrilla sabotage and indirect economic losses caused by the war amounted to nearly US$2 billion during 1979-88, more than the total amount of United States economic assistance provided the country during the same period. Salvadoran officials reported that 2,477 attacks on the country's energy grid in the 1980-87 period destroyed 654 primary and secondary distribution lines, costing US$51 million to repair.

Data as of November 1988