Angola accused South Africa today of carrying out two air strikes on Angolan government forces making a major assault on the headquarters of rebel leader Jonas Savimbi.

South Africa, in a statement by a military spokesman in Pretoria, avoided denying the Angolan charge. The exchange of statements reinforced an impression that the latest South African invasion of southern Angola, launched Monday and billed here as a "hot pursuit" raid against Namibian guerrillas using sanctuaries there, is aimed more at relieving the pressure on Savimbi's South African-backed guerrillas of the National Union for the Total Liberation of Angola (UNITA).

Today's Angolan statement, the Luanda government's first official reaction to the South African invasion, was issued by Defense Minister Pedro Maria Tonha. Tonha said that South African Canberra and Mirage aircraft had dealt "massive blows" to Angolan Army units pressing close to the southern headquarters of the pro-western UNITA rebel movement, which has been fighting to topple Angola's Marxist government since independence from Portugal in 1975.

The official Angolan news agency Angop echoed Tonha in a report that said the invasion was staged to divert international attention from South Africa's domestic strife. The agency quoted unidentified western military experts as saying the South African operation was in support of UNITA.

A UNITA spokesman in Lisbon acknowledged that rebel-held areas in southeastern Angola had been under attack by 25,000 government troops for the past two months. But he said the offensive had been stopped at least 250 miles north of UNITA's headquarters at Jamba and denied the South African action was aimed at relieving its forces.

But the Angop report, quoting a Defense Ministry communique, said that the South African air strikes took place 12 miles from Mavinga, "on the way to Jamba," and claimed they were intended "to help UNITA forces under pressure from government troops."

Asked to confirm or deny the Angolan accusation, a spokesman at South African Defense Force headquarters in Pretoria said tonight: "This statement is probably directed at the Angolan people and armed forces in an attempt to bolster their morale in the present offensive against UNITA. The South African Defense Force has nothing to add to its statements with regard to our action against SWAPO terrorists in southern Angola." SWAPO, the South-West Africa People's Organization, is the guerrilla group fighting for the independence of South African-ruled Namibia.

An official spokesman refused to respond more specifically to the Angolan accusation. However, a spokesman at South African defense headquarters in Windhoek, the Namibian capital, said tonight that South Africa had launched an air attack on a SWAPO command post in southern Angola. The spokesman said the results of the attack were not yet known.

Earlier today, a formal statement from defense headquarters in Pretoria referred only to "intensive reconnaissance and search flights" being made in support of nearly 500 South African and Namibian troops said to have crossed the border in a seek-and-destroy raid against SWAPO guerrillas.

Special correspondent Peter Wise in Lisbon contributed to this report.