Rhodesian counterinsurgency operations extended into Zambia after Zimbabwe People's Revolutionary Army (ZIPRA) rebels shot down two unarmed Vickers Viscount civilian airliners (Air Rhodesia Flight 825 on 3 September 1978 and Air Rhodesia Flight 827 on 12 February 1979) with Soviet-supplied SA-7 heat-seeking missiles. In retaliation for the shooting down of Flight 825 in September 1978, the Rhodesian Air Force attacked the ZIPRA guerrilla base at Westlands farm near Lusaka in October 1978, warning Zambian forces by radio not to interfere.