The Battle of Annual was the only major battle of the Rif War of the 1920s, fought on 22-9 August 1921 between the 3,000-strong army of Abd el-Krim's Berber Republic of the Rif and Manuel Silvestre's 23,000-strong Spanish army. The Spanish Army launched an offensive into the Moroccan countryside, having already secured the coastal areas, and they established makeshift blockhouses (manned by between 12 and 20 troops) as they advanced. On 15 January 1921, the Spanish established a base at Annual. Over the next few months, however, the Berber rebel leader Abd el-Krim led his guerrilla army to overrun isolated Spanish outposts. On 14 July, the Riffians besieged the Spanish outpost at Igueriben, near Annual, and, after five days of skirmishing, 5,000 Spanish troops at the advance camp at Annual were attacked by 3,000 Riffian fighters. The loss of the Spanish supply based at Igueriben and his men's low ammunition supply forced General Silvestre to evacuate Annual, but what was intended to be an organized withdrawal instead became a chaotic rout towards Melilla. The retreating Spaniards were shot or stabbed by pursuing Berbers, and Silvestre disappeared, with some of his men reporting that he had been killed and was found lying face-down on the battlefield. 3,000 Spanish soldiers were massacred by the Riffians at Monte Arruit after the Riffians reneged on their promise to grant the Spanish a safe surrender, but, following the massacre, most of Abd el-Krim's army disbanded, having defeated the Spanish and mistakenly believed that their victory was final. Abd el-Krim was thus unable to besiege Melilla, and, meanwhile, Spain assembled 14,000 reinforcements from elite units of the Army of Africa to defend Melilla and recapture Monte Arruit in November 1921.