In June 1977, Argentine army forces in Entre Rios, Corrientes, and Missiones went on alert; while across the Rio Uruguay, Brazilian garrisons throughout Rio Grande do Sul readied themselves. The nerve center at Santa Maria vibrated with activity and even friendly military observers were warned away.
Some months previously the book El Espacio Argentino by Pablo R. Sanz had been published in Argentina outlining various hypotheses of how a war with Brazil might be conducted (Sanz, 1976: 335-351). The book had been circulated through the Brazilian general staff. Although it carried nothing new for the intelligence services, its publication was taken as an indication of Argentine attitudes.