Jerry Alfred Whitworth, a retired Navy communications officer accused of participating in the Walker espionage ring, testified today that FBI agents subjected him to "psychological warfare" when they questioned him and searched his home two weeks before his arrest last June.

"I felt desperate," Whitworth, 46, said in the first testimony by any of the four defendants in the Walker spy case.

At a hearing before federal Judge John P. Vukasin, Whitworth's lawyers tried to show that even though their client signed forms permitting a search of his mobile home in Davis, Calif., and waiving his rights to remain silent and to consult a lawyer, he did so under improper duress.

"I felt like I was under a great deal of pressure," Whitworth testified. "I felt like I was being bombarded psychologically . . . . I just sort of felt that this would give me some relief, if I signed this thing."

Whitworth's attorneys, James Larson and Tony Tamburello, have asked the judge to suppress the statements Whitworth made under questioning May 20 and the evidence obtained in searches that afternoon, hours after John Anthony Walker Jr. was arrested in a Rockville motel, and on May 31.

None of that information was revealed during the court hearing today. The hearing will continue Monday.

If the motions are granted, Assistant U.S. Attorney William Farmer said during a recess, prosecutors would view the development as a "serious consideration" that might delay Whitworth's trial, now scheduled for Jan. 13.

Whitworth is a longtime friend and Navy colleague of John Walker, who pleaded guilty in October to spying for the Soviets since 1968. Whitworth, a retired Navy senior chief radioman, is accused of receiving $332,000 from Walker in return for giving him classified information, including cryptographic "key cards" and "key lists" that the Soviets could use to decipher codes.

As part of his plea agreement, Walker agreed to testify against Whitworth, and has been here this week to give testimony before a federal grand jury.

According to an FBI affidavit in the Whitworth case, the FBI office here received three letters last year from "RUS," who "stated that he had been involved in espionage for several years and had passed top secret cryptographic keylists" to a contact who had been spying for the Soviets for 20 years. The affidavit states that the FBI believes that Whitworth is RUS.

Michael McElwee, a former FBI agent who questioned Whitworth, testified at today's hearing that when he showed one of the RUS letters to Whitworth and asked if he recognized it, "He stared at the letter for . . . what seemed like a long time, about 90 seconds or so, and then he looked up . . . and said he didn't want to answer that question," McElwee said.

McElwee said that at one point in the interview, Whitworth said he wanted to get a drink of water but instead walked to a different area of the mobile home and "appeared to be placing two pieces of paper underneath the keyboard" of his computer.

Whitworth, a balding, bearded man, answered the lawyers' questions in a brisk, initially confident voice that seemed to falter as the morning went on.

Whitworth, who is charged with espionage and tax violations, testified that when one of the agents began questioning him "very sternly and forcefully," he began to feel mounting anxiety about what was to happen to him and his wife, Brenda Reis.

"Mr. Whitworth," Farmer asked, "hadn't you been fearing for 10 years that you would get a knock on your door one day and it would be FBI agents?"

Whitworth's attorney objected, but Judge Vukasin overruled him and Farmer pressed on: " . . . Because of 10 years of activity that you'd had with John Walker?"

"No," Whitworth said.