Hostilities between Peru and Ecuador began on July 5, 1941, when fire was exchanged between both parties. The events themselves, however, are disputed. According to Ecuador, a group of Peruvians, including policemen, crossed the Zarumilla River into Ecuadorian soil. The Peruvian policemen are then said to have fired first when a border patrol was spotted.Rodríguez, 1955: 168 According to Peru, the Ecuadorian Army shot first at local Civil Guard troops, which exchanged fire for 30 minutes, holding back a potential advance and waiting for reinforcements. After the 5th, hostilities along the border continued. As a result, on the night of July 6, the senior commander of the Ecuadorian Army ordered the formation of the 5th Infantry Brigade in El Oro, under the command of Colonel Luis Rodríguez.Rodríguez, 1955: 173
