The first three hostages released from the besieged U.S. Embassy in Tehran arrived at a U.S. Air force hospital here this afternoon and were described by State Department officials as in "good physical condition and excellent spirits considering what they've been through."

The two black U.S. Marines and a woman employe of the embassy were being kept isolated in a special wing of the hospital while a team of eight doctors and psychiatrists, most of them flown here from the United States, examined them.

The first thing the returnees -- 22-year-old Kathy Jean Gross of Cambridge Springs, Pa.; 23-year-old Marine Sgt. William E. Quarles of Washington, D.C., and Sgt. Ladell Maples, 23, of Earle, Ark. -- did after arriving here was to call their families and take a bath.

On their arrival in Frankfurt, about 20 miles west of here, they were greeted by Under-Secretary of State for Political Affairs David Newsom, who had come in from Washington this morning.

State Department spokesman George Sherman said at a briefing here several hours after the trio arrived that the former hostages really did not want to talk to the press here, at least today, because they went through a "terrible experience" in Tehran last night involving a three-hour press conference with some 250 newsmen. They talked there "exhaustively and exhaustingly" he said.

Asked why, if the patients were in good health and spirits, the stop here was necessary, Sherman said that an examination was necessary to determine that. Moreover, he said, doctors have found through experience that a period of "decompression" was helpful in allowing the returnees to put their ordeal behind them. The main idea, he repeatedly stressed, was to give them time to relax and prepare for their return to their families in the U.S.

The big Air Force military hospital complex here is considered to be the best U.S. medical facitlity in Europe.

Sherman refused to comment on reports that one reason for the stopover here was also to allow military intelligence and State Department officials to debrief the returnees in private, to inquire about the condition of the 59 other U.S. hostages that were still in the embassy as of early today and also perhaps about the situation surrounding the embassy compound.

Sherman acknowledged however that "obviously the State Department and the Marine Corp are interested in what has happened to their people."

Throughout his briefing here today, Sherman stressed that he was not the spokesman for the three returnees and would not discuss their personal experiences or attitudes.

It may also be assumed that officials did not want anything being said here or elsewhere that could prove troublesome for those still held captive, and officials said privately they doubted if there would be an press access to the former hostages during their stay here.