Angola has announced that it is breaking off talks with the United States over a peace settlement in southern Africa in retaliation for a congressional vote allowing American aid to antigovernment Angolan guerrillas.

The move, announced yesterday in the Angolan capital, Luanda, deals another blow to the Reagan administration's 4 1/2-year effort to negotiate a comprehensive agreement that would lead to a withdrawal of Cuban troops from Angola along with independence for the neighboring South African-controlled territory of Namibia.

In its statement, the Angolan Foreign Ministry said congressional repeal of the Clark amendment, which since 1976 has banned aid to rebel Angolan movements, was part of a joint effort by the United States and South Africa to "destabilize the legitimate governments of southern Africa."

The interests in the region of the United States and white-ruled South Africa were "perfectly identical," the statement added.

It continued: "The American administration and the Pretoria government must be held responsible for the escalation of violence in this part of the continent."

Although Washington has no diplomatic relations with the Marxist government in Luanda, diplomats from the two countries have held a series of meetings during the past three years in a search for a regional peace accord.

The most important breakthrough came last year when Pretoria and Luanda agreed to form a joint military commission to monitor the withdrawal of South African forces from southern Angola. Prior to the agreement, South Africa had staged periodic raids into Angolan territory in pursuit of Namibian guerrillas fighting South African rule of their native land.

American diplomats had hoped the withdrawal accord would be the first step toward a settlement of both the Namibian and Cuban issues. They were encouraged further late last year when Angolan officials appeared to concede publicly for the first time the possibility of linking the two issues. Nearly 25,000 Cuban troops are reported to be in Angola.

South Africa announced in April that it was withdrawing its remaining soldiers from Angola. But in late May, Angolan forces killed two South African commandos and captured a third allegedly on a sabotage mission inside northern Cabinda Province. Last month South African troops moved into Angolan territory again, claiming they killed 57 Namibian guerrillas in retaliation for rebel attacks inside Namibia.

The U.S. House of Representatives repealed the Clark amendment last Wednesday on a 236-185 vote. The Senate passed a similar measure in June.

While the administration has welcomed the repeal, saying it would give the United States more flexibility in setting foreign policy, officials said there were no immediate plans to begin funding anti-Marxist Angolan rebels, who are led by Jonas Savimbi and who receive arms and other support from South Africa.

The Clark amendment, named after former senator Dick Clark (D-Iowa), was passed by Congress following revelations of Central Intelligence Agency involvement in Angola's civil war.

The amendment's repeal and the Angolan reaction appear to leave American diplomats almost back where they started in 1981. The diplomats have said repeatedly that one of their biggest problems in the negotiations has been to persuade Angola's wary government of their good faith.

Luanda's leadership has been badly divided over talks with the United States. Some factions have argued that the negotiations were merely an American ploy ultimately designed to force the government to negotiate a power-sharing accord with Savimbi or to buy time while Savimbi built his forces to overthrow the government altogether.

South African Foreign Minister Roelof F. (Pik) Botha disputed today Angola's claim that his government and Washington were working together to undermine Angola, pointing to the U.S. Senate vote this week imposing economic sanctions on South Africa.

"Only the Angolan government can explain how it reconciles the punitive measures being planned against South Africa by the American Senate and House of Representatives with the allegation that the American Congress and South Africa are in league," he said.

South Africa has made clear that it will stay in Namibia, in defiance of United Nations resolutions, until Angola agrees to send home its Cuban troops.

Last month South Africa installed a new local government in Windhoek, the Namibian capital, a step many analysts see as further setting back the prospects for a settlement in the foreseeable future.