Mugabe sees Zimbabwe incursion as proof of South African plot

The almost constant war of words between Zimbabwe and South Africa has taken a military turn.

At least that is the charge from Zimbabwe Prime Minister Robert Mugabe, who claims three white South African soldiers were killed in an engagement on Zimbabwe soil about a week ago.

For Mr. Mugabe, the bodies represent tangible evidence of his often-repeated claim that Pretoria is actively trying to destabilize his government. He is using the incident to try to gain international condemnation of South Africa and sympathy for difficulties in his country that stem from Pretoria's hostility.

South Africa has not explicitly responded to the claim on the grounds that it has not received any official government-to-government protest, but such protest is unlikely, since the two countries do not have diplomatic relations.

The only reaction has come from the South African Defense Force, which says there was no authorized operation into Zimbabwe. Still, it has ordered an investigation.

The three white bodies have not yet been positively identified, nor has their alleged mission in Zimbabwe been spelled out. But the engagement in southeastern Zimbabwe near the border with Mozambique has raised suspicion that the intruders had some connection with the guerrilla Mozambique National Resistance Movement - also alleged to be a tool of South African destabilization efforts.

The South African Defense Force's response that no action was authorized into Zimbabwe is not convincing many of Pretoria's critics. Last year's failed coup attempt in the Seychelles was aided by some members of the South African Defense Force and used Defense Force arms, although Pretoria insists it was not a sanctioned operation.

The charge of armed aggression by South Africa exacerbates its already acrimonious relations with Zimbabwe. The rift has showed no signs of narrowing since Zimbabwe gained independence more than two years ago.

In a recent interview with editors of South African newspapers, Mr. Mugabe ruled out any diplomatic rapproachement with Pretoria. He declined to follow the example of Zambia President Kenneth Kaunda, who disregarded the sentiments of most of black Africa earlier this year by meeting South African Prime Minister Pieter W. Botha.

The growing internal turmoil in Zimbabwe has become a political issue in South Africa. During a recent by-election for a provincial seat near Johannesburg, right-wing whites cited Mugabe's black government as evidence of the ultimate disaster that awaits South Africa, should it start down the road of ''power sharing.''

Zimbabwe has been hit by violence with increasingly political overtones since Mugabe fired his main political opponent, Joshua Nkomo, from the Cabinet in February.

Some 40 people have been killed in armed attacks and robberies, mostly in the western part of the country, where Mr. Nkomo has his support. The widely publicized and still unsolved kidnapping of six white tourists last month was allegedly carried out by Nkomo supporters. Just after the kidnapping nearly one-quarter of Zimbabwe's Air Force was damaged in an attack by saboteurs.

Mugabe has not yet linked the growing internal dissident activity with actions by Pretoria, but Zimbabwe's security concerns are obviously at a high pitch now.