Verde or Operation Green Sea on 22 November 1970 in an attempt to overthrow Ahmed Sékou Touré, the leader of the Guinea-Conakry and staunch PAIGC ally, to capture the leader of the PAIGC, Amílcar Cabral, and to cut off supply lines to PAIGC insurgents. The operation involved a daring raid on Conakry, a PAIGC safe haven, in which 400 Portuguese Fuzileiros (amphibious assault troops) attacked the city. The attempted coup d'état failed, though the Portuguese managed to destroy several PAIGC ships and free hundreds of Portuguese prisoners of war (POWs) at several large POW camps. One immediate result of Operation Green Sea was an escalation in the conflict, with countries such as Algeria and Nigeria now offering support to the PAIGC as well as the Soviet Union, which sent warships to the region (known by NATO as the West Africa Patrol) in a show of force calculated to deter future Portuguese amphibious attacks on the territory of the Guinea-Conakry. The United Nations passed several resolutions condemning cross-border attacks of the Portuguese military against the PAIGC guerrilla bases in both neighboring Guinea-Conakry and Senegal, like the United Nations Security Council Resolution 290, United Nations Security Council Resolution 294 and the United Nations Security Council Resolution 295. Between 1968 and 1972, the Portuguese forces increased their offensive posture, in the form of raids into PAIGC-controlled territory. At this time Portuguese forces also adopted unorthodox means of countering the insurgents, including attacks on the political structure of the nationalist movement. This strategy culminated in the assassination of Amílcar Cabral in January 1973. Nonetheless, the PAIGC continued to increase its strength, and began to heavily press Portuguese defense forces. This became even more apparent after the PAIGC received heavy radar-guided anti-aircraft cannon and other AA munitions provided by the Soviets, including SA-7 shoulder-launched anti-aircraft missiles, all of which seriously impeded Portuguese air operations.Chilcote, Ronald H., The Struggle for Guinea-Bissau, Africa Today, July 197?), pp. 57–61 After the Carnation Revolution military coup in Lisbon on 25 April 1974, the new revolutionary leaders of Portugal and the PAIGC signed an accord in Algiers, Algeria in which Portugal agreed to remove all troops by the end of October and to officially recognize the Republic of Guinea-Bissau government controlled by the PAIGC, on 26 August 1974 and after a series of diplomatic meetings. Demobilized by the departing Portuguese military authorities after the independence of Portuguese Guinea had been