sentences:  After the return of Juan Perón to Argentina, marked by the 20 June 1973 Ezeiza massacre which led to the split between left and right-wing Peronists, and then his return to the presidency in 1973, the ERP shifted to a rural strategy designed to secure a large land area as a base for military operations against the Argentine state.The ERP leadership chose to send Compañía de Monte Ramón Rosa Jiménez to the province of Tucumán at the edge of the long-impoverished Andean highlands in the northwest corner of Argentina.By December 1974, the guerrillas numbered about 100 fighters, with a 400-person support network, although the size of the guerrilla platoons increased from February onwards as the ERP approached its maximum strength of between 300 and 500 men and women.