A top military leader of South Africa's main exiled resistance movement says his organization is not yet ready to lay down its arms in return for talks with the white-minority government and plans to intensify its sabotage campaign inside South Africa.

In his first interview with a western news organization, Joe Slovo, chief of staff of the military wing of the African National Congress (ANC), told The Washington Post, "This is no time to talk to them because we're not strong enough to impose anything on them."

The three-hour interview took place last weekend in an African capital that, under conditions stipulated by ANC officials, cannot be identified.

Slovo, 58, a former lawyer and a Communist who left South Africa 22 years ago, heads the government's most-wanted list and has been portrayed by police there as the white master terrorist who has manipulated the movement's black majority toward Marxist ends.

He is alleged to have planned most of the ANC's major sabotage and terrorist operations, including four explosions at the country's sole nuclear power plant in 1982 and the 1983 car bomb blast outside Air Force headquarters in Pretoria that killed 19 persons and injured 200, many of them civilians.

Slovo denied he had planned the Pretoria bombing but said he did play "a productive and useful role" in the movement's military operations. He said while he regretted civilian casualties, some were inevitable in the armed struggle that was necessary to force the South African government to change.

Slovo strongly denied recent reports in South Africa that his movement was planning to attack white civilian targets but he said it would step up assaults against the country's police and soldiers.

"It's not enough just to deal with the other side's economic targets," he said. "We've got to engage his personnel. More and more as the struggle increases in intensity, this is what we should be doing."

The interview was held before the publication in London of an interview with Nelson Mandela in which the imprisoned ANC leader was quoted as saying the movement would lay down its arms in return for meaningful talks and legal political status inside South Africa. Later, the South African government said it would not consider talking to the ANC until it had proven "over a considerable period of time that violence had in fact been abandoned."

Slovo, who predicted talks between the two sides would occur someday, did not appear to openly contradict Mandela but indicated that he did not believe South Africa would engage in meaningful negotiations until it was forced to. But the contrast between the two statements suggested there are at least some shades of difference between active participants in the organization and Mandela, who during 21 years in prison has become both the movement's most potent symbol and its spiritual leader.

While calling for intensified military action, Slovo emphasized it was just one part of a strategy to force revolutionary change and that political actions such as strikes, boycotts and demonstrations were of equal or greater importance.

"We've got no illusions," he said. "We're not going to destroy the regime just with sabotage blows even if we managed to double or triple the scale of activities. But they still play a fundamental role because the movement can't succeed without creating sufficient armed force to compel change."

He called 1985 "a watershed year" in the eventual overthrow of white rule, saying the combination of internal divisions within the dominant white Afrikaner minority and growing mood of unrest and anger among South Africa's black majority could combine to make this "a very vital year which contains the seeds of a fundamental transformation."

"I think the other side is in bigger trouble today than it's ever been in its history, economically and politically," Slovo said. "The white establishment faces a political crisis of inordinate proportion. They are at each other's throats and the divisions among them are growing."

Slovo left South Africa in 1963 just weeks before a police roundup of ANC leaders broke the back of the underground resistance movement there. Since then he has been a fugitive with a treason charge on his head, living in London and various African nations.

Friends said he and his wife, Ruth First, a South African academic and fellow ANC member, moved to Maputo after Mozambique gained independence under a Marxist government in 1975. From there he is alleged to have conceived and organized dozens of sabotage operations inside South Africa. Those operations came to a halt, and Slovo left Maputo after Mozambique and South Africa signed a nonaggression pact last year.

Slovo laughingly denied South African allegations that he is a colonel in the Soviet KGB.

He branded as a "horrific lie," claims made in South Africa that he played a role in the murder of his wife, who was killed by a letter bomb in Maputo in August 1982. He said he is convinced she was murdered by South African agents who believed she represented a potential threat to their efforts to construct a political detente with Mozambican officials with whom she was personally and politically close. South African officials have denied any involvement in her death.

Slovo spoke freely about political and personal matters but would not divulge details of ANC military activities. The only other matter he skirted was his views on Mozambique. The ANC is trying to rebuild relations with Mozambique that were badly strained in the aftermath of its treaty with South Africa.

Slovo conceded that the ANC had been set back by the accord, which led Mozambique to expel hundreds of its members.

Nonetheless, he said, growing opposition among blacks in South Africa, as demonstrated by last year's riots, school boycotts and a two-day general strike by black workers in Transvaal province, was partly the result of ANC leadership and encouragement. He cited a recent poll of the South Africa Institute for International Relations in which 43 percent of white respondents said they believed the government should hold talks with the ANC.

"For the first time it is recognized by most of the more realistic members of the South African ruling establishment and many of its friends outside that there can be no real solution without the ANC," he said.

"We'll win in the end -- there's absolutely no question. And in a way every battle until the last is a defeat. The question is whether by our defeats and setbacks we are creating the experiences and organization to better equip us to go on to the next stage of the struggle."

Slovo said he was greatly encouraged by the growth of the anti-South African protest movement in the United States, contending such a movement if it grows and continues "could save thousands of lives" by contributing to a less violent end to white minority rule. He said he thought South African President Pieter W. Botha's speech last Friday to Parliament announcing limited new rights for some urban blacks was partly in response to criticism from the West.

Referring to U.S. protests against apartheid, Slovo said, "If all this leads to really serious measures by the West against the regime, economically in particular, it will open up possibilities for some kind of fundamental transformation short of an apocalypse."

Slovo said South African officials were wrong to claim he and other whites were manipulating the resistance movement. "They've become victims of their own ideology in that they can't grasp that it is possible for people of different races to work together without a white man dominating," he said.

He also denied that the movement is under the thumb of Moscow and the South African Communist Party, although he said the party held "a precious and unique position" within the ANC. "We have jealously safeguarded the independence of the organization and avoided behaving in any kind of manipulative way," he said.

Slovo said the Soviet Union had given the ANC "enormous support throughout our history," but had never tried to take control of the movement. "It has never in my experience happened that we were told in the ANC what to do or say" by Moscow, he said.