In the following years, Cuba kept itself engaged in a number of other African countries. In 1978, Cuba sent 16,000 troops to EthiopiaOgaden War, but this time in close coordination with the Soviets. Smaller military missions were active in the People's Republic of the Congo, Guinea, Guinea-Bissau, Mozambique and Benin. Cuban technical, educational and medical staff in the tens of thousands were working in even more countries: Algeria (Tindouf), Mozambique, Cape Verde, Guinea-Bissau, Guinea, Ethiopia, São Tomé and Príncipe,Tanzania, the Congo and Benin. Up to 18,000 students from these countries studied on full Cuban scholarships per year on the island.
Towards the end of the 1970s and into the 1980s, Angola slipped away from wider international public attention but despite Cuba's victory on the ground, the war in Angola was far from over. UNITA was able to take up its insurgency operations in the south with the help of military and logistical support from South Africa and the Angolan government still had not gained control over the whole country. While the vast majority of the Cuban troops remaining in Angola stayed in the bases, some of them helped in 'mopping-up' operations, clearing remaining pockets of resistance in Cabinda and in the north. The operations in the south were less successful because of "Savimbi's tenacity and determination to fight on". "Most of the Cubans were organized and deployed in motorized infantry, air defense, and artilleriy units. Their main missions were to deter and defend against attacks beyond the southern combat zone, protecting strategic and economically critical sites and facilities, and provide combat support, such as rear-area security for major military installations and Luanda itself. At least 2000 Cuban troops were stationed in oil-producing Cabinda Province". After the South African retreat South West Africa People's Organization (SWAPO) again established bases in southern Angola, now supported by the Angolan government, and stepped up its operations in Namibia. In turn, as of early 1977, South African incursions into Angola were on the increase.
Cuban forces soon again were increased due to tensions between Angola and Zaire in March 1977 (see Shaba I). Mobutu accused Angola of instigating and supporting an attack of the FNLC (Front National pour la Libération du Congo) on the Zairian province of Shaba and Neto charged Mobutu with harbouring and supporting the FNLA and FLEC. Only 2 months later the Cubans played a role in stabilizing the Neto government and foiling the Nitista Plot when Nito Alves and José van Dunem split from the government and led an uprising. While Cuban soldiers actively helped Neto put down the coup, Alves and Neto both believed the Soviet Union supported Neto's ouster, which is another indication of the mutual distrust between the Soviets and Neto as well as the differing interests between the Soviets and the Cubans. Raúl Castro sent an additional four thousand troops to prevent further dissension within the MPLA's ranks and met with Neto in August in a display of solidarity. In contrast, Neto's distrust in the Soviet leadership increased and relations with the USSR worsened. Thousands of people were estimated to have been killed by Cuban and MPLA troops in the aftermath of Nito's attempted coup over a period that lasted up to two years, with some estimates claiming as high as 70,000 murdered.
Angola's Cuando Cubango province
In 1977 Britain, Canada, France, the Federal Republic of Germany (West Germany), and the United States formed an informal negotiating team, called the Contact Group, to work with South Africa to implement a UN plan for free elections in Namibia. The South African government, however, was fundamentally opposed to the UN plan, which it claimed was biased in favour of the installation of a SWAPO government in Namibia.
South Africa continued to support UNITA, which not only took up the fight against the Angolan government but also helped the South Africans hunt down SWAPO, denying it a safe zone along Angola's southern border. They SADF established bases in Cuando Cubango Province in south-eastern Angola and the South African Air Force (SAAF) supplied UNITA with air cover from bases in Namibia. South Africa also went to great lengths to brush up Savimbi's image abroad, especially in the US. Apart from being a friend to some African dictators Savimbi became the toast of the Reagan White House and was feted by the rightwing establishment in many countries. Beginning in 1978, periodic South African incursions and UNITA's northward expansion in the east forced the Angolan government to increase expenditures on Soviet military aid and to depend even more on military personnel from the USSR, East Germany and Cuba.
The first large-scale incursions by the SADF occurred in May 1978 (Operation Reindeer), which became South Africa's most controversial operation in Angola. It involved two simultaneous assaults on a heavily populated SWAPO camps at Cassinga(Kassinga) and Chetequera. SADF intelligence believed Cassinga to be a PLAN (People's Liberation Army of Namibia, the armed wing of SWAPO) camp. The operational order was "to inflict maximum losses", but where possible, to "capture leaders". In the air borne raid on 8 May 1978 (SADF-terminology: Battle of Cassinga) over 600 people were killed, including some women and children. In addition, up to 150 Cubans of a unit rushing to the camp's aid lost their lives in an air attack and ambush on the way from their garrison in Tchamutete 15 km to the south. Thus, Cuba suffered its highest single-day casualty of its Angolan intervention. According to the controversial findings of the Truth and Reconciliation Commission, the camp most likely served civilian as well as a military purposes and the raid constituted a breach of international law and the "commission of gross human rights violations". SWAPO and the international media branded the incident a massacre turning it into a political disaster for South Africa. The revulsion at the carnage of the "Cassinga raid" and the ensuing international outcry led to the adoption of UN Security Council Resolution 435 on 29 September 1978, calling for Namibia's independence and, to that end, for the establishment of a "Transition Assistance Group". Pretoria signed the resolution which spelled out the steps for granting independence to Namibia and raised expectations "that peace was around the corner in Southern Africa".
In Resolution 447 of 28 March 1979, the UN Security Council concluded "that the intensity and timing of these acts of armed invasion are intended to frustrate attempts at negotiated settlements in southern Africa" and voiced concern "about the damage and wanton destruction of property caused by the South African armed invasions of Angola launched from Namibia, a territory which South Africa illegally occupies". It strongly condemned "the racist regime of South Africa for its premeditated, persistent and sustained armed invasions ... of Angola", its "utilization of the international territory of Namibia as a springboard for armed invasions and destabilization of ... Angola" and demanded that "South Africa cease immediately its provocative armed invasions against ...Angola". On 2 November 1979 the UN Security Council passed yet another resolution (454), branding South Africa in a similar fashion for its armed incursions, calling upon South Africa "to cease immediately all acts of aggression and provocation against ... Angola" and "forthwith to withdraw all its armed forces from Angola" and demanding that "South Africa scrupulously respect the independence, sovereignty and territorial integrity ... of Angola" and that "South Africa desist forthwith from the utilization of Namibia, a territory which it illegally occupies, to launch acts of aggression against ... Angola or other neighbouring African States". Nevertheless, by the end of 1979, following the bombing of Lubango, an undeclared war was in full swing.
Hardly 2 weeks later, on 17 May 1978, 6,500 Katangese gendarmes invaded the Zairian province of Shaba from bases in eastern Angola (Shaba II invasion) and the US accused Cuba of having a hand in it. Although there is no proof for a Cuban involvement it is likely that the Katangese had the support of the Angolan government. They were driven back across the border by French and Belgian military and Cuba and the US coaxed Neto and Mobutu to sign a non-aggression pact. While Neto agreed to repatriate the Katangese Mobutu cut off aid to FNLA, FLEC and UNITA and their bases along the border were shut down. By late 1978 Angola's security had been steadily deteriorating and UNITA emerging as a formidable guerrilla army, expanding its operations from Cuando Cubango into Moxico and Bié while the SADF intensified its cross-border campaigns from Namibia.
Neto died on 10 September 1979 while seeking medical treatment in Moscow and was succeeded by Jose Eduardo Dos Santos. Barely one month later Ronald Reagan became President of the United States, immediately adopting a harder line with Angola: The Cubans were absolutely to be driven out of Angola.
In elections held in February 1980; the leader of the leftist Zimbabwe African National Union (ZANU) and outspoken opponent of apartheid, Robert Mugabe, was elected president, ending white minority rule in Zimbabwe. Losing its last ally (Rhodesia) in the region, South Africa adopted the policy of "Total Onslaught" vowing "to strike back at any neighbouring states which harboured anti-apartheid forces". On 10 June 1980 Pretoria launched its largest operation since World War II, 180 km into Angolan territory, during which, for the first time, it was attacked by the FAPLA. In the following September, the SADF assisted UNITA in the capture of Mavinga.
In the early 1980s, the United States, in their endeavour to get the USSR and Cuba out of Angola, became directly involved in negotiations with Angola. Angola pointed out it could safely reduce the number of Cuban troops and Soviet advisors if it wasn't for the continuing South African incursions and threat at its southern border. The most obvious solution was an independent Namibia which South Africa had to give up. After having to accept a leftist regime in Angola, Pretoria was reluctant to relinquish control of Namibia because of the possibility that the first elections would bring its "traditional nemesis", SWAPO, to power. It continued to attend negotiating sessions of the Contact Group throughout the early 1980s, always prepared to bargain but never ready to settle. Cuba, not involved in the negotiations, basically agreed to such a solution paving the way to Namibia's freedom. Yet, towards the end of Reagan's second term in office, the negotiations had not born any fruit.
After the UN-sponsored talks on the future of Namibia failed in January 1981, (South Africa walked out of the Pre-Implementation Conference in Geneva on 13 January in April 1981 the new American Assistant Secretary of State for African Affairs, Chester Crocker, took up negotiations combining 'constructive engagement with South Africa' with the 'linkage' proposal (independence for Namibia in change for Cuba's withdrawal). Both Angola and South Africa deeply distrusted the US for various reasons and the idea was rejected. It continued to be the basis of further negotiations; yet, the Contact Group members as well as the 'frontline states' (states bordering South Africa) were opposed to linking Namibian independence with Cuban withdrawal. Despite its overwhelming presence in Angola, the Cubans remained uninvited to the negotiations.
The same year, South African military activity increased against Angolan targets and SWAPO guerrillas. On 23 August 1981, the SADF launched an invasion Operation Protea with eleven thousand troops penetrating 120 kilometres into southwestern Angola and occupying about 40,000 km² in southern Cunene (holding the territory until 1988). Bases were established in Xangongo and N'Giva. The South Africans not only fought SWAPO but also wanted FAPLA out of the border area and openly intensified assaults on Angolan economic targets. The US vetoed a UN Resolution condemning the invasion, instead insisting on Cuba's withdrawal from Angola. Within five months of the South African invasion the Soviets started a new two-year military programme for the FAPLA to which Cuba committed another 7,000 troops. FAPLA-Cuban forces refrained from larger actions against South African operations, which were routinely undertaken deep into Angolan territory following Operation Protea. Through 1982 and 1983 the SAAF also participated in operations by UNITA, which gained more and more control of south-eastern Angola. The attacks by far exceeded the previous hit and -run operations and were aimed primarily at the Benguela Railway. Increasingly Cubans got involved in the fighting, either because they had garrisons in the embattled area or because they came to the rescue of FAPLA units under attack. The civil war had a crippling effect on the Angolan economy, especially agriculture and infrastructure, created hundreds of thousands of refugees. UNITA guerrillas took foreign technicians as hostages.
On 6 December 1983 Pretoria launched its twelfth incursion, Operation Askari, in pursuit of SWAPO which was also to inflict as much damage as possible on FAPLA's increasing military presence in southern Angola. In protest, France and shortly after Canada, left the UN Contact Group. On 20 December the UN Security Council passed yet another resolution (546) demanding withdrawal and reparations by South Africa. Unlike during Operation Protea this operation was met with strong resistance by the FAPLA-Cuban forces leading to the fiercest fighting since independence. A battle ensued after a SADF attack on a SWAPO camp near Cuvelei (northern Cunene) on 3 – 7 January 1984. Although SWAPO suffered a severe defeat in this campaign the South Africans were unable to unseat the FAPLA from bases at Cahama, Mulondo and Caiundo as it had planned. Under growing international pressure Pretoria stopped the operation and retreated south of the border on 15 January but kept the garrisons in Calueque, N'Giva and Xangongo. A cease fire between Angola and South Africa was signed on 31 January, the first treaty between Luanda and Pretoria. Peace negotiations were taken up again and in February 1984 Crocker met with Angolans and South Africans in Lusaka, Zambia. The resulting first 'Lusaka Accord' of 16 February 1984 detailed the disengagement of Angolan and South African forces in southern Angola. Already during this process the accord was doomed to fail because SWAPO was not involved in the talks and continued its operations. UNITA also stepped up its raids including mine-laying, truck bombs, hostage taking and attacking foreign civilians as far north as Sumbe.
In a joint statement on 19 March 1984 Cuba and Angola announced the principles on which a Cuban withdrawal would be negotiated: unilateral withdrawal of the SADF, implementation of Resolution 435 and cessation of support for UNITA and armed actions against Angola. Cuban withdrawal would be a matter between Cuba and Angola. In a similar joint announcement in 1982 these principles had been formulated as demands. The proposal was rejected by Botha. In September 1984 Angola presented a plan calling for the retreat of all Cubans to positions north of the 13th parallel and then to the 16th parallel, again on the condition that South Africa pulled out of Namibia and respected Resolution 435. 10.000 Cuban troops around the capital and in Cabinda were to remain. A major obstacle in the negotiations was the timeline for the withdrawal of Cuban troops. While Pretoria demanded a maximum of 7 months the Cubans wanted four years. Crocker managed to reduce the Cuban's timeline to two years upon which the South Africans suggested only 12 weeks. Crocker then proposed a timeline of 2 years and a withdrawal in stages and a maximum of 6,000 troops remaining up to another year in the north. But both parties and UNITA rejected this proposal and the negotiations stalled. On 17 April Pretoria installed an 'Interim Government' in Namibia which was in direct contravention of Resolution 435. The Lusaka Accord completely fell apart when South Africa broke the cease-fire. On 20 May 1985 it sent a commando team to blow up an American-run Gulf Oil facility in northern Angola. The raid failed, but it showed that Pretoria was "not interested in a cease-fire agreement or the Namibian settlement to which a cease-fire was supposed to lead."
On 10 July 1985 the US Congress rescinded the 10-year-old Clark Amendment. Within a year at least seven bills and resolutions followed urging aid to UNITA, including overt military support and some 15 million US dollars. As of 1986 the US openly supported UNITA.By 1986 the war reached a stalemate: FAPLA was unable to uproot UNITA in its tribal stronghold and UNITA was no serious threat to the government in Luanda. Within a week Pretoria, suffering from internal unrest and international sanctions, declared a State of Emergency.
Cuban troops were alleged to have used nerve gas against UNITA troops during the civil war. Belgian criminal toxologist Dr. Aubin Heyndrickx, studied alleged evidence, including samples of war-gas "identification kits" found after the battle at Cuito Cuanavale, claimed that "there is no doubt anymore that the Cubans were using nerve gases against the troops of Mr. Jonas Savimbi."