Battle of Zarumilla and the 1941 Military Campaign

The Battle of Zarumilla, fought between July 23 and July 31, 1941, was the decisive theater of the northern military campaign that consolidated Peru's territorial integrity along its border.

Faced with repeated incursions and fortified enemy redoubts on the left bank of the Zarumilla River, President Manuel Prado activated the Agrupamiento del Norte on January 11, 1941, under Brigadier General Eloy Gaspar Ureta Montehermoso, with Lieutenant Colonel Miguel Monteza Tafur as Chief of Staff and Lieutenant Colonel Manuel A. Odría directing operations.

The Peruvian forces (over 9,800 troops) deployed an advanced combined-arms doctrine integrating infantry, combat engineers, 75 mm and 105 mm artillery, naval units in the gulf, aviation wings, and crucially, the Armored Detachment equipped with 12 Czechoslovak-built ČKD Praha LTP light tanks (model 1938). This represented the first deployment and maneuver of armored warfare in combat in South American history.

Between July 23 and 26, the Peruvian offensive crossed the Zarumilla River. The rapid thrust of the armored tanks through river crossings, synchronized with dive-bombing close air support, shattered enemy defensive lines at Chacras, Huaquillas, Carcabón, and Huabillos, forcing the opposing 5th Brigade to retreat inland toward Arenillas. The victory halted all territorial ambitions and established complete Peruvian tactical control over the border zone.