The top Democratic and Republican leaders of Congress met with President Carter yesterday and said afterward they believe his charges that Cuba helped train and equip the rebels who invaded Zaire last month.

The congressional leaders made that unanimous assertion following a 45-minute White House meeting at which Adm. Stansfield Turner, director of the Central Intelligence Agency, presented some of the evidence on which the administration has based its accusations against Cuba.

Attending from Congress were Senate Majority Leader Robert Byrd (DW. Va.), House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), Senate Minority Leader Howard H. Baker Jr. (R-Tenn.) and House MInority Leader John J. Rhodes (R-Ariz.).

None of the four would discuss the nature of the evidence they were shown, saying it could not be revealed for fear of exposing government intelligence sources. However, they left no doubt about the impression the evidence had made on them.

Baker said, "I'm convinced beyond a shadow of a doubt that there has been Cuban involvement and Russian in the invasion . . . I think the Cubans are lying."

"There's no doubt in my mind the president is telling the truth," O'Neill added.

Rhodes agreed, saying: "The allegations made by TUrner and the sources they gave convinced me that he knows what he's talking about."

Byrd left the meeting by a side door without talking to reporters. But a spokesman for his office said Byrd also had been "convinced the president has accurate information" on the Cuban role in the Zaire invasion.

The nature of the administration's intelligence information has been the subject of speculation and controversy ever since the president and high administration officials began making the charges against Cuba last week.

Cuban President Fidel Castro's government has denied the accussations, and some members of Congress, most notably Sen. George McFovern (D-S.D.), have called on the administration to show its evidence to the Congress. The administration has said it will do so at what it considers the appropriate time.

Also present at yesterday's White House meeting were Vice President Mondale and National Security Affairs Adviser Zbigniew Brzezinski.