The Carter administration yesterday showed Congress some of the evidence - satellite photographs and reports from diplomats and prisoners - on which President Carter based his charge that Cuba assisted the rebel invasion of Zaire last month.
Reliable sources said the evidence, presented by Central Intelligence Agency Director Stansfield Turner to a closed session of the House Intelligence Committee, consisted mostly of information collected from rebel prisoners, diplomats and persons in countries surrounding Zaire.
In addition, the sources said, Turner displayed various satellite photos that he said showed rebel encampments near the Zaire border and a Cuban ship being unloaded in Angola, the neighboring Marxist country from which the rebels launched their attack on Zaire's Shaba Province.
Although the evidence was described by the sources as largely circumstantial, committee Chairman Edward P. Boland (D-Mass.) said, "I'm satisfied, and the committee itself is satisfied, that the president's statement was correct."
His words added the committee's backing to the support given Carter last week by the top leadership of Congress: Senate Majority Leader Robert C. Byrd (D-W. Va.) and Minority Leader Howard H. Baker Jr. (R-Tenn.), House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) and Minority Leader John J. Rhodes (R-Ariz).
Ater a meeting with Carter and Turner at the White House on Friday, all four said they believed the president's charges that Cuba helped train and equip the invading force.
However, it was not immediately clear whether this growing congressional support will end the questions and doubts that have been expressed about whether the administration has sufficient evidence to prove its charges against the Cuban government of President Fidel Castro.
These doubts have come from some members of Congress, most notably Sen. George McGovern (D-S.D.), and from some officials of the administration itself. The officials, who have asked not to be identified, have said the evidence appears too circumstantial and too susceptible to differing interpretations to be conclusive.
Turner, speaking to reporters after his two-hour session with the committee yesterday, tried to address that point, saying:
"To sum up, we have made a very careful and objective evaluation of this evidence. In intelligence, nothing can be black and white. But from the preponderance of the evidence and the variety of sources over a period of time, we can only come to the conclusion that we did."
Almost certain to add to the controversy was the revelation by administration sources yesterday that none of the evidence will be classified and made public - at least not under present White House plans.
The sources said public disclosure had been considered but was rejected out of fear it would reveal the CIA's sources and methods of collecting information.
As a result, they added, current plans call only for the evidence to be given to the Intelligence and Foreign Relations committees of Congress on a restricted, nonpublic basis. That decision, one source said, seems certain to be adehered to even "if it means a credibility gap."
Despite a statement yesterday by House Speaker O'Neill that the administration had evidence of Cubans in Zaire, the administration has said only that Cuba helped to train and equip the rebels in Angola and that Havana knew of the plans for the invasion and did nothing to stop it.
Turner underscored that point anew yesterday. "This government made no statement that Cubans were in Zaire or they were not. The evidence is not clear one way or the other," he said.
Among those who have seen or been briefed on some of the evidence, the biggest argument involves the reliability of the sources from whom the CIA obtained its information.
Persons present at yesterday's committee briefing said Turner reffered to sources only in such general terms as "an African diplomat" or a "man believed to have been one of the rebel invaders who was wounded and interviewed while a hospital prisoner."
Asource who has seen one of the intelligence reports in question noted, though, that it contained a CIA notation that the African diplomat who provided the information had never been used before and was therefore of unknown reliability.
One committee member said the most detailed identification given by Turner yesterday involved a Belgian national who was taken prisoner by the invaders and transported to a rear area, apparently in Angola, for execution.
However, the committee member said, the man spoke Spanish and used that language to plead successfully with persons in command over his captors for his release.