South Africa steps up its campaign against guerrillas

South Africa's relentless drive to deprive the African National Congress of bases from which to launch its guerrilla attacks is showing results. Lesotho, one of the prime targets of Pretoria's campaign, has persuaded a number of South African exiles - who may or may not be members of the outlawed ANC - to leave its territory. Although Lesotho maintained that the 68 exiles were political refugees, South Africa insisted that they posed a security threat.

Pressure against Lesotho was part of a concerted campaign by South Africa to keep the banned ANC from operating from black states in the region. The campaign has been particularly visible over the past year or so. It was acknowledged by the chief of the South African Defense Force earlier this year following an ANC attack in Pretoria that took 19 lives.

Over the past year South Africa has also forced greater cooperation from Swaziland, which like Lesotho is a small black-ruled nation that is strategically placed. It allows easy ANC infiltration into South Africa. Firm diplomatic pressure from Pretoria resulted in a Swaziland clampdown on the activities of so-called ''refugees.''

Pretoria also used an incident of ANC insurgency in June to warn Zimbabwe not to alter its stand on ANC activity. Zimbabwe policy does not allow the ANC to operate from its territory. In that incident South Africa allegedly captured some ANC members who entered the republic through Zimbabwe.

The result of South Africa's actions is that the government has effectively isolated Mozambique as the only bordering black state that it regards as a serious ANC collaborater.

Pretoria regards Mozambique as the prime launching pad of ANC attacks and has retaliated with two strikes of its own into that country. The strikes have not been in isolation. South African and Mozambique ministers have held several meetings at the border town of Komatipoort to discuss security issues. Mozambique alleges that South Africa is supporting a resistance movement in that country.

In spite of Pretoria's apparent success in containing the ANC and not allowing it more bases from which to operate, the outlawed group continues to strike regularly on South African soil. The strikes are of no military consequence. But they are carefully targeted to achieve maximum publicity, with the apparent dual aim of alarming whites and inspiring admiration among blacks.

Lesotho became the recipient of dire warnings from South Africa toward the end of 1982. Pretoria claimed Maseru was being used as a ''starting point'' for recruiting members of the ANC who were then flown to Mozambique for training.

Lesotho denied the allegations. But South Africa took matters into its own hands in December last year with a devastating strike on Maseru against alleged ANC members. Some 42 persons were killed in the raid, including a dozen innocent bystanders.

Relations between Lesotho and South Africa have continued to worsen this year , even though Lesotho is heavily dependent economically on South Africa. South Africa has imposed strict border controls on the tiny nation. Lesotho for its part has charged that South Africa is the staging ground for attacks by the Lesotho Liberation Army, seeking the overthrow of the Maseru government.

During a recent trip to southern Africa, United Nations Secretary-General Javier Perez de Cuellar arranged for UN officials to meet with Lesotho leaders to try to reach an agreement on South Africa's demands that certain ''refugees'' be resettled outside Lesotho. Lesotho claimed the exiles were leaving ''voluntarily.'' South Africa termed the action ''constructive.''