Vice President Mondale told Nigeria officials tonight that America's national interests are tied to the future of newly indepedent Zimbabwe because circumstances there "will help decide" subsequent events in white minority-ruled South Africa and Nambia.

In a reference to domestic turmoil and antigovernment guerrilla attacks that have plagued the racially segregated Pretoria government in recent weeks, Mondale said, "The clock is ticking in South Africa."

Mondale's comments came against the backdrop of an editorial in today's progovernment Daily Times, Nigeria's leading newspaper, which sharply criticized what it said was the small amount of aid pledged by the Carter administration to Zimbabwe.

On South Africa's controversial policy of racial segregation, the Times editorial said the Carter administration policy has "degenerated almost to indifference." The Times often reflects government views.

The comments by Mondale and this government's stress on South African issues indicated U.S.-Nigerian relations may be again at a crossroads. They reached a low during the Angolan civil war five years ago.

Senior U.S. officials, however, sharply disputed a comparison with 1975.

Nigeria, the most powerful country in black Africa, is the focus of Mondale's week-long visit in west Africa, the first by any American vice president. Before arriving here on Sunday, Mondale stopped in Senegal and uranium-rich Niger.

Mondale is leading a 72-member trade mission to Nigeria, the second supplier of oil to the United States after Saudi Arabia. American officials are seeking to increase exports to Lagos, which enjoy an estimated $11 billion trade advantage with Washington this year -- exceeding Japan's estimated $8 billion trade surplus with the United States.

At a dinner, hosted by Nigerian Vice President Alex Ekueme, Mondale said the Carter administration had maintained trade sanctions against the former white-minority government of Rhodesia under "intense pressure to abandon this course -- to jettison our principles and take a shortsighted view of our interests."

"We know that it is in our national interest to support further progress for Zimbabwe," Mondale said. "The United States had pledged substantial assistance to Zimbabwe, because we believe that its future will help decide the future of southern Africa."

The U.S. government has given Zimbabwe $20 million in aid this year and has applied for a congressional appropriation of $30 million for next year, said Assistant Secretary of State for African Affairs Richard Moose.

Nigerian officials were not immediately available for comment but the Daily Times criticized the amount of U.S. aid to Zimbabwe. "Zimbabwe is free." the editorial read, "but has not received the scale of economic aid the Americans hinted at, if not promised," before independence.

A senior U.S. official has characterized the relationship with Nigeria as "vulnerable" and "dependent" because 16 percent of America's oil imports came from here. They comprise 47 percent of Nigeria's 2.2 million-barrel daily production.

"There is nothing that we're doing for them that is equal to what they're doing for us," the official said. "It is not just a fiscal imbalance, but a political imbalance."

The low point in U.S. Nigerian relations, during the 1975-1976 Angolan civil war, resulted from revelation that the CIA covertly aided the South African-backed guerrilla forces fighting the Soviet-backed and Cuban-led Marxist guerrillas now in power there.

In recent years, however, U.S. foreign policy largely has dovetailed with Nigeria's on Zimbabwe.

"We kept the faith on Zimbabwe," the U.S. official said, "and it has changed our relationship" with the Nigerians. "We can now talk to them like we talk to the Canadians and they are giving us the benefit of the doubt."

A close relationship with Nigeria's 10-month-old civilian government is important, the official continued," because the Nigerians swing enormous weight in terms of African opinion."

Nevertheless, one high Nigerian official, who declined to be indentified, said, "We are just not sure" what the American government will do on South Africa and Namibia now that Zimbabwe is independent under majority black rule.

Mondale said the American government is urging South Africa "to build on the experience of Zimbabwe and to move forward -- not backward -- on the issue of Namibia, while there is still time."

South Africa has ruled Namibia, also known as Southwest Africa, under a League of Nations mandate since the end of World War I. Western nations have tried to pressure South Africa into accepting a U.N. plan for supervised elections leading to independence. The South African Army recently invaded southern Angola to pursue guerrillas allegedly based there.

"If South Africa does not accept the plan," Mondale continued, "if it insists on its own formula and carries the conflict further afield into neighboring states, the opportunity for peace could be lost and the conflict will continue."