ATLANTA, NOV. 29 -- Federal officials brought in three prominent Cuban Americans tonight to explain to more than 1,000 Cuban inmates holding 90 hostages in the federal prison here the terms of an agreement that ended a similar uprising in Oakdale, La., by granting limited protection from deportation.

The appearance of the three, all from Miami, and all of whom had participated in the contacts with the inmates earlier in the week, capped a day of easing tensions during which authorities restored water service to the prison and the mood of inmates and families grew almost festive.

Patrick S. Korten, spokesman for the Justice Department, refused to characterize the discussions in any way other than to say that the three met with three inmate negotiators for about an hour and then with a much larger group for another hour. He said authorities do not know how many attended the larger meeting.

Korten identified the three Miamians as Cuban exiles Roberto Martin Perez, Armando Valladares and Jorge Maas Canosa. Martin and Valladares are former prisoners of the Cuban regime of Fidel Castro, and Maas Canosa is chairman of the foundation that supports the anti-Castro Radio Marti and also was President Reagan's Florida campaign chairman in 1984.

The three were last known to be at the prison on Thursday. Unlike Miami Mayor Xavier Suarez and a group who arrived with him, the three who met with the inmates tonight had been brought into the negotiations with federal cooperation.

Korten deflected most questions, but with several inmates' wives who had infiltrated the hastily called outdoor news conference crowding near him, he assured reporters that all inmates and their hostages were in good condition.

"There's no indication anyone has been injured or is otherwise suffering," he said.

As night fell, the prison grew quiet under hazy but cold skies, a marked contrast to Saturday night, when two buildings were burning and inmates were shouting slogans over loudspeakers.

Meanwhile, Miami Auxiliary Bishop Agustin A. Roman, who played a key role in today's release of 26 Cuban-held hostages in Oakdale, said in an evening news conference there that he is willing to go to Atlanta.

But Roman, who was born in Cuba, told reporters at a briefing following the end of the hostage drama in Oakdale that he had not been asked by the Atlanta inmates to assist in the negotiations. The Roman Catholic bishop said that if the inmates "call, I will go."

Earlier today, dozens of inmates shouted anti-Castro diatribes and pleas for fair treatment over the loudspeakers and waved U.S. and Cuban flags from a rooftop in clear sight of an armed guard tower still under the control of authorities.

Justice Department spokesman Thomas M. Stewart avoided characterizing the restoration of water as a negotiating ploy, but made it clear that authorities were rewarding inmates for the release of four hostages early today.

Ninety hostages remain in the prison with 1,119 Cubans and 20 U.S. prisoners. A small number of prisoners have given up each day since the prison was taken Nov. 23.

The Atlanta situation took a dramatic and sometimes confusing turn Saturday night when inmates for the first time began using the two-way prison radio system to broadcast a set of demands -- mainly that they be allowed to remain in the United States, that their cases be reviewed by courts rather than the Justice Department, that they be given help finding jobs and that there be no reprisals.

Fires then broke out in two prison buildings, which continued to smolder today.

Shortly after midnight, in a move that took authorities by surprise, inmates called the FBI negotiators to say they would release four hostages, demanding only television coverage of the release in return.

The four -- whom Stewart described as popular with the inmates -- were Carl Gates, 54, the prison's chief of psychology; Walter Cassady, 63, a psychiatrist; Lawrence Greer, 43, a social worker, and Manuel Echevarria, 37, an English teacher. Stewart said they apparently had been treated well.

In one of the more dramatic events of this evening, one of the released hostages, Echevarria, made a videotape supporting the Cubans and distributed it to the news media.

"The Cubans' plight should be heard," he said. "Even after six days of hostage-taking, they have shown themselves to be men in every sense of the word." Reporters were not allowed to question the four released hostages.

Stewart said that resolution of the Oakdale hostage drama does not necessarily portend a quick end to the Atlanta takeover. "The Oakdale detention center is quite a bit softer in penal terms," Stewart said.Staff writer Ruth Marcus in Washington and special correspondent Michael Rezendes in Oakdale, La., contributed to this report.