The People's Revolutionary Army, founded in the early 1970s, is considered the most militarily powerful of the five armed factions in the rebel Farabundo Marti National Liberation Front. Its commander, Joaquin Villalobos, has built up an army estimated at between 1,500 and 2,000 troops. These fighters operate in highly mobile units. Aside from regular military forces, the ERP has organized the elite Rafael Arce Zabala brigade and specialized mobile columns. The ERP works closely with guerrilla factions in Usulutan and northern La Union provinces of El Salvador.
The guerrilla group is not as ideologically dogmatic as other groups in the FMLN but is generally considered Marxist in its orientation. It is also influenced by the writings of Mao Tse-tung, and it briefly established official relations with China, although it now promotes nonalignment. Initially it had poor relations with the Cuban government, but its rapport with Havana is now considered good.
The ERP operates the clandestine ''Radio Venceremos'' heard each night on FM and shortwave throughout El Salvador.