South Africa's salvos at tiny black neighbor Lesotho could backfire

Tensions are rising between South Africa and Lesotho, similar to those that preceded Pretoria's devastating strike into that country late last year. And South Africa's hard-line policy toward its tiny landlocked neighbor appears to be backfiring. Lesotho's political belligerence toward South Africa seems only to be growing.

Lesotho, known mostly for its wool and mohair weaving, got unwanted attention last December when South Africa invaded its capital city of Maseru to attack members of the banned African National Congress.

The ANC is conducting a sabotage campaign against South Africa's white government. Some 42 people were killed; Pretoria concedes a dozen of them were innocent bystanders.

Despite a brief rapprochement, relations between the two countries in the wake of the strike continue to go from bad to worse. Lesotho claims Pretoria wants nothing less than to topple its government. South Africa says it has ''had enough'' of such claims and is threatening military and economic action against Lesotho if it persists in providing alleged sanctuary to the ANC - a charge Lesotho denies.

South Africa's threats were contained in a letter to the United Nations Security Council earlier this month.

The most serious long-term development creating friction between the two states is Lesotho's rather rapid development of friendlier ties with the East bloc.

Lesotho Prime Minister Chief Leabua Jonathan announced recently that five communist countries would be opening embassies in his country over the next year. The Soviet Union, China, and North Korea are to open embassies before the end of this year, followed in 1984 by Romania and Yugoslavia.

Pretoria sees Soviet influence behind the sabotage campaign being waged by the ANC, and the opening of the embassies in Lesotho is regarded by South Africa as a provocative act.

The welcoming of Eastern diplomats is a risky move for Chief Jonathan, and is something of an about-face for him. Jonathan has been in power since Lesotho became independent in 1966, and early on received the backing of South Africa for his moderate and pragmatic policies.

But the relationship has been strained since the early '70s. In 1970, Jonathan aborted a general election that would have caused his downfall to a more radical opposition. Since then, he has stepped up his anti-South Africa rhetoric to drum up more domestic political support as well as more international aid, while deftly avoiding going so far as to bring the full wrath of Pretoria.

But now he appears to have gone too far in the eyes of South Africa.

Chief Jonathan also faces the prospect of political turmoil at home. The Roman Catholic Church is powerful in Lesotho, and there is mounting criticism from the church over the opening of communist embassies in the country.

Jonathan also faces a home-grown guerrilla movement. Some of his opponents who fled the country after the aborted 1970 elections formed the Lesotho Liberation Army. They have carried out acts of sabotage and assassination against the government. The LLA is widely believed to operate from South African soil, and Lesotho charges it has South African support.

Early last month South Africa and Lesotho agreed to clamp down on ''subversive elements'' operating from their respective territories. But talks to implement that agreement have broken down.

The growing friction between the two countries is surprising because of Lesotho's extreme vulnerability to South Africa. The tiny country is a virtual economic ward of South Africa, with three-quarters of its wage earners working as migrant laborers in South Africa.

When a bomb exploded in the South African city of Bloemfontein earlier this year, Pretoria retaliated with a partial blockade of the main Lesotho border post, crippling tourism and commerce. But so far, Lesotho has refused to cower before such South African pressure.