The supposedly clandestine Bay of Pigs invasion of Cuba in 1961 by American-trained, armed and transported Cuban exiles was such a poorly kept secret that it was openly discussed in the bars of Miami, according to testimony made public yesterday by the Senate Foreign Relations Committee.

Transcripts showed for the first time that three reporters testified before the committee soon afterward in a postmortem on the disastrous invasion.

The transcripts do not mention President John F. Kennedy's private appeal to the press to withhold news of the impending invasion -- which he later told The New York Times he came to regret profoundly.

The testimony about the botched invasion coincides with new disputes between government and press over invoking "national security" to keep a story out of the news -- notably the Pentagon's unsuccessful attempt to block news stories last week about military missions of the space shuttle.

In the Bay of Pigs operation, a landing force of some 1,400 Cuban exiles trained by the Central Intelligence Agency was swiftly crushed by Cuban government troops, a military fiasco that devastated the fledgling Kennedy administration.

Advance information about the landing of April 17, 1961, literally was available in Miami in March to any reporter who wanted it. Tad Szulc, then a correspondent for The New York Times, told the Senate Foreign Relations subcommittee on American Republic Affairs that he first heard of plans for the invasion in July or August of 1960.

Szulc appeared before the subcommittee two months after the landing, in June 1961, along with The Times' Max Frankel, now editor of that newspaper's editorial page. Their testimony followed that of earlier testimony by Henry Raymont, then a correspondent for United Press International, who was jailed in Havana for six days while the invasion was under way.

"I remember the first day in Miami," Szulc said, "I was at a bar in a hotel with some Cuban friends and I said, 'Well, I would like to know more about it the invasion plan . Where can I get some information?' "

The response, Szulc said, was that the CIA was in charge of it: "You are an American newspaperman. Why don't you go to the CIA?"

Szulc said that when he asked who to talk to, he was told, " 'Here is the name of the people we work with. Why don't you telephone them?' I said, 'Is it really that simple?' They said, 'Yes, of course.' "

"Everybody but the United States Senate" knew that, Sen. Homer E. Capehart (R-Ind.), a subcommittee member, said wryly. "And, evidently, the president of the United States . . . ."

On April 7, Szulc testified, The New York Times, "after a great deal of soul-searching" and after hearing that others were "on the track of the story," published portions of what it knew in a front-page story.

Szulc said that when he reached Cuba after the landing was crushed, and found "almost 1,200 prisoners" out of about l,400 men who landed, Castro told him he had been "absolutely sure" about the operation, except for the exact date and site.

Years later, in a 1966 speech, Clifton Daniel, then managing editor of The Times, disclosed that the Szulc story was toned down after Kennedy appealed to the editors on national security grounds. But shortly after the landing, when it proved to be a foreign policy disaster, Kennedy told editors of The Times: "If you had printed more about the operation, you would have saved us from a colossal mistake."

The appearance of all three newsmen before the subcommittee headed by Sen. Wayne Morse (D-Ore.) was entirely voluntary, and the request raised no question of journalistic propriety in their minds, Szulc, the main witness, said yesterday in an interview.

"It never had the formal appearance that it seems to have today," he said. "I guess we were very innocent about such things in those days." They were responding "out of a sense of courtesy" to people they knew well, he said, and "it was like having tea with the subcommittee" that had asked, "would you be kind enough to come and share with us what you have seen?"

These days, Szulc said, for many "there is almost a sinister aspect" to such requests.