Asturias Offensive The Asturias Offensive ( ) was an offensive in Asturias during the Spanish Civil War which lasted from 1 September to 21 October 1937 . 45 , 000 men of the Spanish Republican Army met 90 , 000 men of the Nationalist forces . Background . After the failed republican offensive against Zaragoza , the Nationalists decided to redeploy their forces and continued their offensive against the last piece of Republican held territory in the Norh , Asturias . On 29 August , the Sovereign Council of Asturias , led by Belarmino Tomas , assumed all military and civil powers and appointed Colonel Prada as commander of the Republican Army of the North . Opposing forces . The Nationalists offensive was launched by the General Dávila ' s Army of the North , with 80 , 000 men . This force included the José Solchaga ' s four Navarrese brigades , the Aranda ' s three divisions and the Italian " CTV " . The Nationalists also had 250 cannons and 250 aircraft . Opposing them , the Republicans had the Army of the Norh , led by the Colonel Prada , with the XIV Army Corps led by Francisco Galán ( 8 , 000 – 10 , 000 men ) and the Colonel Linares ' s XVII Army corps ( 35 , 000 ) . The Prada ' s chief of staff was Francisco Ciutat . The Republicans had 180 cannons , one squadron of " Chatos " and two flights of " Moscas " , around 35 aircraft . The Nationalist Offensive . The Nationalist offensive started on 1 September , Solchaga advancing from the East and Aranda from the southwest , but despite their crushing numerical and air superiority their advance was painfully slow ( less than a kilometre a day ) . The Republicans fought fiercely and the difficult terrain of the " Cordillera Cantabrica " provided excellent defensive positions . The Solchaga ' s troops ( 33 , 000 men ) occupied Llanes on September 5 and attacked the El Mazuco pass , held by the " CNT " workers from " La Felguera " ( 5 , 000 men ) . The Navarrese managed to conquer the Pass , only after 33 days of bloody combats . On September 18 the Nationalists occupied Ribadesella , on 1 October Covadonga , but by 14 October , the Republicans still held several high passes of the Leonese Mountains . The main goal of the Republicans was to delay the Nationalist advance until the winter came , nevertheless , then the " Legion Condor " returned from the Aragon front and started to bomb the Republican positions . The German squadrons used napalm ( cans of petrol attached to incendiary bombs ) and tested the idea of the carpet bombing . On 14 October Arriondas fell , and the Colonel Muñoz Grandes managed to break the republican front , entering in Tama and advancing to Campo de Caso . The Republican troops retreated to Gijón and on 15 October the Solchaga ' s troops joined up with Aranda ' s troops . Then , the Republican government ordered to begin the general evacuation and on 17 October the Sovereign Council of Asturias decided to start the evacuation , but the " Legion Condor " sank the Republican destroyer " Ciscar " and the Nationalist fleet blocked the Asturian harbours . Only the senior officers managed to escape on gunboats and fishing vessels ( Prada , Galán , Segundo Blanco , Belarmino Tomas ) . On 20 October , twenty - two Republican battalions surrendered and the Colonel José Franco , handed over the town of Trubia to the Nationalists . On October 21 , the Nationalists entered Gijon , ending the occupation of Asturias . Nevertheless , thousands of Republican soldiers fled to the nearby mountains and started a guerrilla campaign against the Nationalist troops . Aftermath . The Nationalist repression was harsh . In Oviedo alone , 1 , 000 republican prisoners were shot . The Republican prisoners were sent to labour battalions or were forced to join the Nationalist army ( around 100 , 000 ) . Furthermore , with the conquest of the North , the Nationalist controlled the 36 per cent of the Spanish industrial production , 60 per cent of the coal and all the steel production .