in Tete region, putting its efforts on the two northernmost districts of the country where the use of landmines became very common. In the region of Niassa, FRELIMO's intention was to create a free corridor to Zambézia. Until April 1970, the military activity of FRELIMO increased steadily, mainly due to the strategic work of Samora Machel in the region of Cabo Delgado. In the early 1970s, after the Portuguese Gordian Knot Operation, the nationalist guerrilla was severely damaged. Role of the Organisation of African Unity The Organisation of African Unity (OAU) was founded May 1963. Its basic principles were co-operation between African nations and solidarity between African peoples. Another important objective of the OAU was an end to all forms of colonialism in Africa. This became the major objective of the organisation in its first years and soon OAU pressure led to the situation in the Portuguese colonies being brought up at the UN Security Council. The OAU established a committee based in Dar es Salaam, with representatives from Ethiopia, Algeria, Uganda, Egypt, Tanzania, Zaire, Guinea, Senegal and Nigeria, to support African liberation movements. The support provided by the committee included military training and weapon supplies. The OAU also took action in order to promote the international acknowledgement of the legitimacy of the Revolutionary Government of Angola in Exile (GRAE), composed of the National Liberation Front of Angola (FNLA). This support was transferred to the People's Movement for the Liberation of Angola (MPLA) and to its leader, Agostinho Neto in 1967. In November 1972, both movements were recognised by the OAU in order to promote their merger. After 1964, the OAU recognised PAIGC as the legitimate representatives of Guinea-Bissau and Cape Verde and in 1965 recognised FRELIMO for Mozambique. Eritrea Eritrea sits on a strategic location along the Red Sea, between the Suez Canal and the Bab-el-Mandeb. Eritrea was an Italian colony from 1890–1941. On April 1, 1941, the British captured Asmara defeating the Italians and Eritrea fell under the British Military Administration. This military rule lasted from 1941 until 1952. On December 2, 1950, the United Nations General Assembly, by UN Resolution 390 A(V) federated Eritrea with Ethiopia. The architect of this federal act was the United States. The federation went into effect September 11, 1952. However, the federation was a non-starter for feudal Ethiopia, and it started to systematically undermine it. On December 24, 1958—the Eritrean flag was