It is an African guerilla movement like no other. The founders were not black intellectuals or peasants seeking to defeat European colonialism, but rather white spy masters. The movement was born not in the African bush, but in the capital of what was then white-ruled Rhodesia.

Over the last five years the Mozambique National Resistance Movement, through economic shortage and terror tactics, has brought the government of black-rule Mozambique to its knees, forcing it to bargain with white-ruled South Africa. Last Wednesday South Africa announced that the two sides had agreed to a cease-fire.

In the process, analysts say the Mazambique National Resistance Movement has stunted the economic life of five other black nations in southern Africa, forcing them, too, into greater dependence on their hated neighbor to the south.

Created more than a decade ago by Rhodesian intelligence officials who foresaw the collapse of their Portuguese colonial allies in neighboring Mozambique, the Mozambique National Resistance Movement was passed on to South Africa when Rhodesia became black-ruled Zimbabwe in 1980. Nurtured by outside money and South African expertise, it has grown into an effective tool for pressuring not only the Marxist government of Mozambique, but also that of neighboring Zimbabwe, whose fuel, transport and food relief supplies have been threatened with strangulation by the rebels.

Despite South African denials, American diplomats and other analysts are convinced that the Mozambique National Resistance Movement has received most of its support from South Africa and is under Pretoria's control.

That control now is being tested by an agreement made last March between South Africa and Mozambique that commits Pretoria to quelling the insurgency. Its inability to do so suggests to some analysts that forces outside South Africa's control have at least a measure of influence over the movement.

The origins of the resistance movement have been clothed in secrecy for years. But following last week's announcement in South Africa that the government of Mozambican President Samora Machel and the rebel group have declared their intent to seek a truce, a former senior Rhodesian intelligence official who played a major role in establishing the movement in the early 1970s agreed to discuss its birth under the condition that he not be named.

In the '70s, he said, analysts for the Rhodesian Central Intelligence Organization wanted to keep close watch on the more than 500 miles of border Rhodesia shared with Mozambique. They needed information about Frelimo, the Mozambique liberation movement, and about its black Rhodesian guerilla allies who were preparing to launch their own war of liberation against the government of Ian Smith.

Finding Portuguese intelligence capabilities inadequate, they decided to establish their own information network. A training base was established on a farm near the city of Umtali (now Mutare) and later a clandestine radio station known as the Voice of Free Africa was set up and operated from the Rhodesian side of the border.

Recruits poured in, the official said. Many were former Frelimo soliders who had grown disenchanted with the movement's Marxist orientation and who, in some cases, had run afoul of Frelimo's tight code against corruption.

"Normally it is very difficult to set up networks -- the work is hard and the risks are great," said the former official. "But in this case, it was almost too easy. We looked for disaffection which we could latch onto and promote -- and there was plenty of it."

"They were there as an extra set of eyes and ears, and to provide a haven for our people when we went across the border. They accepted our pay, our weapons and our food to build themselves up into a resistance movement.

When Portugal's right-wing government fell in 1974 and Machel assumed power the following year, the Rhodesians stepped up their support for the Mozambique National Resistance Movement. The official said they were inundated with white Portuguese volunteers from the former colonial government. A handful were taken on, he said, but Rhodesia's intelligence director, Ken Flower, resisted others because he insisted on keeping the movement small, manageable, clandestine and African.

"It never exceeded 500 men, and that was done purposely," the source said. "We weren't interested in mercenaries, and we didn't want anyone to be able to say this thing had been created by us. So we kept it small."

There was one exception, he said. The Rhodesians agreed to take on Orlando Cristina, a white Portuguese who had been an aide to Jorge Jardim, one of Mozambique's wealthiest men. Jardin reportedly the late Portuguese dictator Antonio Salazar's personal business representative in Mozambique, had fled after Frelimo took power. Cristina eventually became the number two man in the movement and Jardim reportedly provided funds to help keep the organization alive after the Rhodesians pulled out.

The South African government under Prime Minister John Vorster disapproved of Rhodesian clandestine operations and had warned Ian Smith against setting up the guerilla movement. It was only in 1978, after Vorster's forced retirement and the rise of then-defense minister Pieter W. Botha to the prime ministership, that Pretoria began to express an interest in the movement.

The group's Rhodesian connection began to fray in 1979, when the Smith government agreed to sit down with its black guerilla opponents at the Lancaster House talks in London, the former official said.

The Mozambican rebels were offered three options: bury their arms and return home; leave Mozambique via Rhodesia and settle elsewhere or go to work for the South Africans, who had become eager to take over the operation. "The majority chose to accept South African control, he said.

White Rhodesia became black-ruled Zimbabwe, and in March 1980, within days of the election that brought guerilla leader Robert Mugabe to power, the operation was handed over to South African military intelligence.

The South Africans regrouped the force, brought in fresh supplies and arms and expanded the force with white former Portuguese secret police and military personnel who had fled to South Africa from Mozambique following independence.

Alfonso Dhlakama, a former Frelimo soldier with backing from Cristina and Jardim, became the movement's field commander. According to apparently authentic documents captured in December 1981, the South Africans set up a training base at Zoabostad in the Transvaal and sent specialists and instructors into Mozambique to train the guerillas and participate in raids by the rebel group.

By 1983, the movement was conducting a coordinated campaign against Frelimo. Buses and trains were sabotaged, food supplies from Maputo to remote rural areas were cut off, uncooperative rural peasants had their ears, lips and noses mutilated. The oil pipeline between the Mozambican port of Beira and Zimbabwe was blown up several times and, in perhaps the movement's most audacious operation, two dozen Soviet mining technicans were kidnapped and held for several months.

Kidnap victims and other witnesses to attacks by the resistance movement say the rebels operate in well coordinated units, using sound military tactics. They often appear well-armed and well-fed. But unlike other African liberation movements, the group has never developed its own ideology nor articulated a political alternative to the Marxism it seeks to overthrow.

For several years, the intelligence official said, the Mozambican authorities appeared not to take the movement seriously, dismissing it as a group of mere "bandits." But in 1983 the government launched a series of major counteroffensives that appeared to have some success in curtailing rebel operations.

Nonetheless, by the end of 1983 the rebels were operating in nine of Mozambique's 10 provinces, and at times even in the suburbs of Maputo. The Frelimo government estimated that between 1975 and 1982 the Mozambique National Resistance Movement campaign had cost the country $3.8 billion. Combined with drought and failed government economic policies, the campaign has pushed Mozambique into an economic tailspin that was a key factor in persuading Machel to negotiate the Nkomati agreement with South Africa in March.

Under the pact, Mozambique agreed to curtail sharply the activities of South African black nationalists operating against the Pretoria government from Mazambican territory, in return for a South African commitment to eliminate its support for the Mozambique National Resistance Movement. Mozambique vigorously fulfilled its end of the bargain by expelling most of the nationalists, but the South African-backed group has continued to function without apparent impediment.

Several explanations have been offered, including reports that South African military operatives, aware that their government was nearing a deal with Frelimo, rushed in enough supplies and arms to maintain the rebels for at least a year. It is also clear that the movement is receiving funding independent of Pretoria from Portuguese businessmen in South Africa and Lisbon.

South African officials, for whom the Nkomati accord marked a critical breakthrough from diplomatic isolation, are eager to see Frelimo and the resistance movement sign an accord that will end the bush war.

Ultimately, however, the group's officials appear to be seeking an agreement that will grant them a role in a new, non-Marxist Mozambican government, a concession Frelimo officials insist they will never make. Barring such a deal, many observers expect the war -- and Mozambique's agony -- to continue.