It fell into the hands of Francoist troops Otxandio. The attack began on March 31 by order of General Mola. Its intention was to destroy the northern front that extended from Otxandio and Ondarroa to Asturias. Previously, the planes conducted by the Duñano Ángel Salas Larrazabal and José Muñoz Jiménez bombed the town during the Santamaña holidays and caused 61 deaths and injuries. Mola personally congratulated both. After a harsh air and artillery attack on the positions of the Basque Army, the rebels began the invasion of Bizkaia from the ground.