became known as the "Shipanga Affair". The army was forced to marshal several battalions to subdue the dissidents. In response to Zambia's increasingly open support for PLAN, South Africa sponsored a force of Kaonde-speaking dissidents under Adamson Mushala, known as the Zambian Democratic Supreme Council (DSC). The DSC maintained a low level insurgency in Zambia's North-Western and Western Provinces. Mushala's guerrillas sabotaged infrastructure, skirmished with the ZDF, and collected intelligence on PLAN movements inside Zambia. They were trained by South African special forces and instructors recruited from the Portuguese Directorate-General of Security. In 1973, an army unit killed a hundred of the guerrillas by ambushing them as they attempted to cross the Zambezi near the Caprivi Strip. Mushala was largely inactive until early 1976, when his guerrillas skirmished twice with the ZDF and hijacked an army payroll. As a result of the new challenges posed by the Mushala insurgency and the presence of foreign militants, the ZDF underwent an extensive reorganisation and adopted a new unified command structure. It was renamed the Zambian National Defence Force (ZNDF) in 1976. A prevailing feature of the new ZNDF was its adoption of a third branch known as the Zambian National Service. The objective of the Zambian National Service was to provide basic military instruction to all Zambian citizens in the event they needed to be mobilised as reservists during wartime. The ZNDF became increasingly politicised, with the ruling United National Independence Party (UNIP) forming party branches in the barracks and introducing a number of political education programs for military personnel. Under the UNIP, the ZNDF was not subject to public audit or parliamentary oversight. This was justified under the pretext that the ZNDF's development was tied to the exigencies of wartime. Between 1977 and 1980 military tension with South Africa and Rhodesia continued to escalate, resulting in a renewed spate of border incidents. In 1977, the ZNDF bombarded Rhodesian positions near Victoria Falls with rocket and mortar fire. The reasons for the attack were disputed but the Zambian government maintained that the troops involved had been deliberately provoked by Rhodesian forces into firing. Around March 1978, the ZNDF claimed to have been involved in repelling a Rhodesian raid on a ZIPRA training camp. It also assisted PLAN insurgents during a raid on a South African military base in the Caprivi Strip. South Africa retaliated by shelling several ZNDF positions near the border,