Republican assault The Republican Army spent a week preparing to cross the Ebro. According to the historian
Antony Beevor, the
commandos of the XIV Corps slipped across the river in order to obtain information about the Nationalist positions, and the Republican troops rehearsed the crossing in ravines and rivers on the coast. Some key players, including
Ramón Rufat, explained in detail the intelligence gathering and preparation process. The Nationalist intelligence assets passed back reports to the Nationalist High Command, detailing troop movements and the concentration of the International Brigades, as well as the presence of rafts and pontoon bridges on the other side of the river, but Franco thought that the Republican Army would not be ready to undertake an offensive across the Ebro. The Republican army started the crossing on the night of 24–25 July during a no moon period. Republican commandos crossed the river, killed the Nationalist guards and fastened lines for the assault boats, then the first Republican troops crossed in ninety boats (each of which carried ten men). The remaining troops of the V and XV Corps crossed the next day, using three pontoon bridges and another 12. The surprise was total and Republican forces were initially successful. Nevertheless, a secondary assault near
Amposta, carried out by the XIV International Brigade, failed after 18 hours of combat, and the XIV International Brigade retreated, after suffering huge losses. During the first day, Republican troops surrounded the troops of the Colonel Campos’s 50th Division, taking 4,000 prisoners, and many other Nationalist soldiers deserted. By the evening, Tagueña had advanced three miles in the north and Lister twenty one in the center. By 26 July, the Republican troops had occupied 800 square kilometres and reached the outskirts of Gandesa; nevertheless the Nationalists deployed Barron’s 13th Division in the town and the Republican troops failed to occupy it. Then, Franco decided to send heavy reinforcements to the Ebro’s front (eight divisions, more than 140 bombers and 100 fighters) and passed the order for the dams at
Tremp and
Camarasa to be opened. The flood water destroyed the pontoon bridges, although the Republican engineers managed to repair them within two days. Furthermore, the
Condor Legion and the
Aviazione Legionaria started to bomb and destroy the pontoon bridges each day, although the Republican engineers managed to repair them each night. Because of this, only 22 tanks and a handful of artillery managed to cross the Ebro River, and Republican troops began running low on supplies, ammunition and drinking water.
Siege of Gandesa The key target for the Republicans was the town of
Gandesa, some 25 km west of the Ebro, a crossroads to Catalonia and the north-south roads running parallel to the Ebro. The terrain around the town was extremely hilly, being dominated by the
Cavalls,
Pandols and
Fatarella mountain ranges whose hard and bold
limestone rocks and scant forest cover provided little shelter against Francoist fire. On 27 July, Modesto ordered an attack on Gandesa with T-26 tanks and on 30 July decided to concentrate his tanks and artillery around Gandesa and launched an infantry assault against the city. On 1 August, the XV International Brigade launched a fierce attack against Hill 481 in front of Gandesa, suffering huge casualties; nevertheless, the Republican assault had failed due to the Nationalist air and artillery superiority and Modesto ordered the Army of the Ebro to go on the defensive.
Battle of attrition After the end of the Republican offensive, the Republican army of the Ebro was trapped in a pocket with its back to a river and Nationalist officers wanted to attack across the unprotected
Segre River and advance to
Barcelona, but Franco wanted to destroy the Republican Army of the Ebro and to recover the lost territory. The Nationalists concentrated most of their artillery and air forces in the Ebro's Front. On the other hand, the Republican high command ordered their troops to resist and not to retreat. Officers and men were executed for retreating. The battle was fought by both sides as a
World War I Western Front style battle, with each side launching bloody frontal assaults on enemy positions in what became a
war of attrition. The Nationalist tactic was to use artillery and aerial bombardment in small areas to soften resistance and then to launch a frontal assault with one or two infantry battalions to occupy the area. Each day 500 cannons fired more than 13,000 rounds at the Republican troops and more than 200 Nationalist aircraft dropped 10,000 pounds of bombs. Nevertheless, the Republican troops fought with stubborn bravery and repelled the Nationalist assaults with barrages of machine-gun and mortar fire. In many zones, the terrain was too hard to dig trenches or foxholes, and as the August heat became unbearable (on 4 August it was 37°C in the shade), the shortages of water and food grew worse for the Republican troops. The situation was made more desperate by the relentless bombing that the Republican troops endured from dawn to dusk, which made it impossible for bodies to be buried, and meant that the wounded could only be evacuated at night, by small boats. The key to the battle was Nationalist air superiority, provided by the Italian
Aviazione Legionaria and German
Condor Legion squadrons that flew under the
Aviación Nacional markings. Some 500 first class planes were available on the Nationalist side (
Savoia SM-79,
Savoia SM-81,
BR.20,
He 111,
Do 17,
Ju 52 and 6
Ju 87 bombers, against only some 35 modern fighters and some 40 second class aircraft of the
Spanish Republican Air Force. In July, the Legion Condor had destroyed 76 Republican planes and by August the Republican Air Force had lost air superiority in the area. The Republican planes were outnumbered by at least two to one, and most of the experienced Soviet pilots had been withdrawn. Republican anti-aircraft defenses proved to be inadequate and many planes were destroyed on the ground.
Nationalist counteroffensive The Nationalist forces launched six counter-offensives in order to retake the territory seized by the Republicans. The first counteroffensive was launched on 6 August against the northern republican held pocket between
Mequinenza and
Fayón. The Legion Condor dropped 50 tons of bombs and by the 10 August the Republican troops were forced back across the river. Then Franco decided to send Garcia Valiño's Maestrazgo Corps to the front and on 31 August the Nationalists launched an attack against the
Cavalls Range in order to advance towards Corbera. The mountain range was held by the 35th, 11th and the 43rd Republican divisions, and the Nationalists attacked with eight divisions, 300 guns, 500 aircraft and 100 tanks. On 3 September the Nationalists launched a new attack from Gandesa supported by German
88 mm guns and by 4 September the Nationalists had occupied Corbera. Then Yagüe's forces broke the Republican lines, but Modesto sealed the breach with the 35th Division and ordered their troops to hold on: "Not a single position must be lost. If the enemy takes one, there must be a rapid counterattack and as much fighting as necessary, but always making sure that it remains in republican hands. Not a metre of ground to the enemy!" After six weeks of combat the Nationalists had recovered 120 square miles. On 2 October the Nationalists occupied the heights of Lavall and two weeks later Point 666, the key of the Pandols Range. On 30 October the troops of the Garcia Valiño's Army Corps of the
Maestrazgo, led by
Mohammed el Mizzian, attacked the heights of the
Cavalls Range, supported by 175 guns and 100 aircraft. The Republicans lost the heights after one day of combat, suffering huge casualties (1,000 prisoners and 500 dead), despite the support of 100 fighters. On 2 November the Nationalists occupied the
Pandols Range and on 3 November the right flank of the Nationalist forces reached the river Ebro. On 7 November
Móra la Nova fell and by 10 November the Nationalists had occupied
Mount Picossa. On 16 November the last men of the 35th recrossed the Ebro at Flix and the battle ended. ==Aftermath==