Directly following on from Operation Moduler, by November 1987 the SADF had cornered the remnants of three FAPLA units on the east of the Cuito River, across from the town itself and was poised to destroy them.

[2] The quite demoralised 59 FAPLA motorised infantry brigade, 21 and 25 FAPLA light infantry brigades, in positions near Tumpo and east of the Cuito River, were effectively cut off due to SADF artillery control of both the bridge and airstrip and to UNITA guerrilla control of the road from Menongue, which they had mined and were prepared to ambush.

[7][page needed] In the opinion of Cuba's leader, Fidel Castro, a South African victory would have meant not only the capture of Cuito and the destruction of the best Angolan military formations, but, quite probably, the end of Angola's existence as an independent country.

Thus Castro responded immediately by sending — in what was called "Maniobra XXXI Aniversario de las FAR" — materiel and 15,000 elite troops, retaking the initiative from the Soviets.

[4] The first Cuban reinforcements in Cuito arrived by helicopter on 5 December 1987 with about 160[8]–200[9] technicians, advisers, officers, and special forces.

[10] The deployment of regular ground forces was authorised on the condition that the Angolan Ministry of Defence allow Cuban general officers to supervise and lead all future combat operations around Cuito Cuanavale.

[6] General Arnaldo Ochoa, a veteran of the 1976 Angola campaign and of tank battles in Ethiopia, was made overall commander of the forces on the government side.

These tensions were to have repercussions both during the war where Castro's interference with defense plans may have cost the Cubans dozens of lives[11] and in the aftermath of Angolan hostilities a year later when Ochoa was arrested, tried and executed by firing squad after being found guilty of treason.

[17][16] The bombardment started on 2 January 1988, with a mix of artillery and air strikes, and a UNITA infantry attack that failed.

[20] The 32 Battalion and elements of other units harried the road convoys for weeks, destroying several hundred tanks and other vehicles, and inflicting an unknown number of casualties.

A large Cuban and FAPLA column was on the way from Menongue for the relief of Cuito Cuanavale, but progress in the rainy season was slow due to the need to clear the UNITA minefields and guard against possible ambushes.