Operation Georgette or the Battle of Estaires to the British. In the Treaty of Versailles, the Portuguese acquired the territory of Kionga from what was once German East Africa. Estado Novo (1926–74) 28 May 1926 coup d'état Military dictatorship (1926–33) Involvement in the Spanish Civil War (1936–39) Salazar gave material and diplomatic aid to Francisco Franco's nationalist forces while maintaining a formal neutrality. A special volunteer force of 18,000, called Os Viriatos (in honour of Lusitanian leader and Portuguese national hero Viriatus), led by regular army officers, was recruited to fight as part of Franco's army, even if unofficially. When the civil war ended in 1939, Portugal and Spain negotiated the Treaty of Friendship and Nonaggression (Iberian Pact). The pact committed the two countries to defend the Iberian Peninsula against any power that attacked either country and helped to ensure Iberian neutrality during World War II. World War II (1939–45) Although Portugal proclaimed neutrality in the conflict, the Japanese Imperial Army invaded the Portuguese Timor colony in distant Oceania, killing thousands of natives and dozens of Portuguese. In response, the Portuguese civilians joined Australia, the Netherlands, the United Kingdom, and the United States against the Japanese. See Battle of Timor. NATO Parachuters (1956) Portuguese–Indian War (1961) The Portuguese–Indian War was a conflict with the Republic of India's armed forces that ended Portuguese rule in its Indian enclaves in 1961. The armed action involved defensive action against air, sea and land strikes by a numerically superior Indian force for over 36 hours, and terminated in Portuguese surrender, ending 451 years of Portuguese rule in Goa. Thirty-one Portuguese and thirty-five Indians were killed in the fighting. Portuguese Colonial War (1961–74) Portugal remained steadfastly neutral in World War II, but became involved in counterinsurgency campaigns against scattered guerrilla movements in Portuguese Angola, Portuguese Mozambique, and Portuguese Guinea. Except in Portuguese Guinea, where the revolutionary PAIGC quickly conquered most of the country, Portugal was able to easily contain anti-government forces through the imaginative use of light infantry, home defense militia, and air-mobile special operations forces, despite arms embargoes from other European countries. During the counterinsurgency campaigns in Angola and Mozambique, Portugal was significantly aided by intelligence provided by native residents who did not support revolutionary forces. However, the ideology of the guerrillas, especially the PAIGC, had a profound impact on the officers of the Portuguese armed forces and a left-wing military coup in Lisbon