A senior Central Intelligence Agency official told Congress he knew about the secret air resupply operation by former White House aide Oliver L. North that aided the Nicaraguan contras in 1986, but he acknowledged in testimony released yesterday that he sat silently last October while superiors gave "cute" answers to Congress that hid the U.S. government role.

"So long as others who knew the details as much as I, {and} who knew more than I, were keeping their silence on this, I was going to keep my silence," Alan D. Fiers, chief of the CIA's Central American task force, told a closed session of the House-Senate Iran-contra committees on Aug. 5.

Fiers was asked about his actions last Oct. 14 during a House Permanent Select Intelligence Committee meeting where members questioned Assistant Secretary of State Elliott Abrams and Claire George, CIA deputy director for operations, about the shootdown the previous week of a C123K cargo plane over Nicaragua that was piloted by Americans.

Abrams denied there was any U.S. government involvement in the flight and George said the CIA was not involved directly or indirectly in the operation.

Fiers testified that he was "taken aback" by Abrams' sweeping denial of U.S. involvement since Fiers knew that North was directing the privately run operation. Fiers also knew that one of his subordinates, the CIA station chief in Costa Rica, was aiding the enterprise.

"My frame of mind was to protect, was to be a member of the team, not to get out ahead," Fiers told the House-Senate panels.

Sen. William S. Cohen (R-Maine), who, as a member of the Senate Select Intelligence Committee, heard similar denials of knowledge about the resupply effort from agency officials last fall, called Fiers part of "a conspiracy of silence of CIA witnesses who came before the committees and each had this silent vow not to be the first one to step forward."

Reflecting a concern about the forthrightness of CIA witnesses that was also voiced by other committee members, Cohen lectured Fiers that "when you are called to testify, I think your obligation runs to something broader and higher than just the agency."

Fiers testified that he believed he had been caught in a "nutcracker" situation when he took the job of running the CIA's Nicaraguan operation in October 1984, days after Congress passed the Boland amendment prohibiting U.S. aid to the contras fighting the government of Nicaragua.

In the testimony and exhibits released yesterday:Fiers testified there was "considerable evidence . . . that people in and around {former contra leader} Eden Pastora were in fact involved in cocaine-running to the United States to raise revenue for their cause." Because of the allegations, Fiers said "it was right not to deal with" Pastora, who attempted for a time to open a southern front from Costa Rica against the Sandinista government. Discussing what he called "the remnants of Pastora's people," Fiers said, "We developed information that they were receiving money from cocaine trafficking."

Ironically, the committees disclosed yesterday they had been unable to corroborate allegations of "U.S. government-condoned drug trafficking by contra leaders and contra organizations or that contra leaders or organizations did in fact take part in such activity," according to a July 23 letter to Rep. Lee H. Hamilton (D-Ind.), chairman of the House panel, that was released with yesterday's exhibits.

Staff counsel Robert A. Bermingham wrote that Dave Faulkner, an investigator with the Senate select committee, said that panel also had come up with "substantially negative" information with regard to contra drug smuggling.

The House investigators interviewed hundreds of individuals, reviewed contra financial records and the files of eight government agencies and discovered "almost all of these allegations orginate from persons indicted or convicted of drug smuggling," Bermingham said.

The committees will turn their files over to the House Judiciary Committee and a Senate Foreign Affairs subcommittee, which are looking into the drug issue. Independent counsel Lawrence E. Walsh also is investigating allegations U.S. officials condoned contra drug trafficking. In October 1986, after Congress approved $100 million for contra aid, Fiers said that CIA Director William J. Casey approved an attempt to solicit additional funds for the Nicaraguan rebels from Taiwan, which had already given $2 million. Fiers testified that he told Casey, who came up with a middleman who had "good connections":

"Right on, boss; we could maybe get that five or six million dollars, and that will allow me to buy two or three more airplanes and do some things and it will be a good thing." Apparently, however, the solicitation never took place. Fiers, who worked closely with Marine Lt. Col. North for several years, said the former National Security Council staff aide had a penchant for stretching the truth.

"I never knew Col. North to be an absolute liar," Fiers said, "but I never took anything he said at face value because I knew that he was bombastic and embellished the record, and threw curves, speed balls and spitballs to get what he wanted, and I knew it and I knew it well."

Pressed by Sen. Sam Nunn (D-Ga.) to explain North's performance before the committees, Fiers went on to say, "I have seen Col. North play fast and loose with the facts. And I think the record will substantiate that. But, on the other hand, I believe that from where I sit, from the glimpses I saw of this thing {North's televised testimony} as the train windows went by, there was a lot of fact in what he said, too." Fiers also shed some light on one of the unanswered questions of the investigation: How the Nicaraguan rebels were financed after July 1986, when U.S. humanitarian aid had ended and almost no funds were provided from contributions or the proceeds from U.S. arms sales to Iran. They borrowed.

Fiers testified that he took over the Central American post at the time the CIA inspector general was investigating the agency's distribution of a manual to the contras on guerrilla warfare that advocated "selective use of violence" to neutralize Sandinista political targets.

"I saw the devastating impact of five letters of reprimand {received by those involved in the manual's distribution}," Fiers said and determined that he would run the task force "so that all the liability, the political heat, falls on me."

During his testimony, however, Fiers repeatedly was presented with documents describing activities with the contras that he said he did not recall or were in error.

He could not recollect an August 1985 cable discussing a controversial airfield being built in Costa Rica for the North resupply network, although he drafted a reply to it. "I don't recall having read the thing, but obviously I did read it," he said.

Although Fiers testified that he learned of the participants in North's operations throughout 1986, Fiers failed to name any of them last Dec. 9, when he appeared before the Senate intelligence committee. When Sen. David L. Boren (D-Okla.) asked him why he did not, Fiers responded: "I can't figure why." Later he added: "I was walking a line once again as a member of a team . . . . It was a very tense sort of moment in time. I was one of the first ones off the block. I was exposed. I was nervous. And I was not going to perjure myself."

Reflecting on the Oct. 14 hearing, when Abrams denied any U.S. government involvement with the contra resupply plane that was shot down, Fiers said, "I was taken aback by the statement . . . . Mr. George was taken aback by his statement."

"I didn't know what the status of Mr. Abrams' knowledgeability was . . . . I didn't ask him how he got there. I didn't get involved with it. I didn't understand. I didn't ask him about it. I just let it sit there," he said.

As for George, Fiers said, he "had the broad strokes, he knew that Ollie {North} had been around and was involved, {but} he didn't know as much detail of the involvement as I did."

Asked about his Oct. 14 testimony, Fiers replied: "It's all part of a passivity that I described to the committee -- just to get through troubled waters and get on to the next program."

In response, Sen. Paul S. Sarbanes (D-Md.) said he did not feel any assurance "that if placed in, as you put it, in the nutcracker again, you wouldn't, in effect, repeat your performance."