QUANTICO, VA., JULY 22 -- Sgt. Clayton J. Lonetree, the Marine Corps guard whose case triggered the spy scandal in the U.S. Embassy in Moscow, went on trial for espionage today before a general court-martial amid claims by his family and lawyers that he has been victimized because of his race.

The trial began with a 30-minute delay caused by a power blackout at the press center set up by the Marines in a nearby building at the training base here.

In the ensuing confusion at the opening, it was not clear whether Lonetree had actually entered a plea to the charges. His chief defense lawyer said Lonetree, 25, had pleaded not guilty, but Marine public information officers later said a formal plea had not been recorded by the trial judge, Navy Capt. Philip Roberts.

Less than an hour later, Roberts ordered the trial into closed session for arguments over prosecution and defense motions. The proceeding remained closed to the media for the rest of the day.

Lonetree's lawyers said later they had moved for dismissal on grounds of misconduct by naval investigators and asked for the entire court-martial to be held in public. But the judge ruled that sensitive material should be heard in private.

Defense lawyer William Kunstler condemned the decision as a deliberate move by the authorities to create an erroneous public impression that important secrets are involved in the case.

Kunstler also said the court had granted the prosecution the right to introduce an "anonymous and classified witness," and said he will challenge this Thursday in the Court of Military Appeals in Washington.

Lonetree, an American Indian, arrived at the trial about 8:30 a.m. Staring straight ahead, he was marched, in uniform, into the small courtroom at base headquarters.

Handcuffed and guarded by five Marines, with one holding each arm, he took his seat between his lawyers to face 13 charges including espionage.

His grandmother, mother and aunt, all carrying eagle feathers and Indian spiritual symbols, sat quietly in the courtroom. They were later joined by his father.

During the day, Lonetree's lawyers and family appeared outside the courtroom, denouncing the proceeding and describing the defendant as a "patriot." Indians demonstrated against the court-martial, played drums and said a peace prayer while Marines looked on.

Claiming Lonetree had been "duped," Kunstler accused the Naval Investigative Service of "incompetence and corruption . . . . Being an Indian made him a good target . . . . They zeroed in on Lonetree because he was vulnerable, could be manipulated and would get little support."

Lonetree's grandmother, Alice Benally, a Navajo from Arizona, whose words were translated by her daughter, May, said, "He is patriotic and loves his country. Now they have thrown him into jail because he was so honest."

Lonetree, from St. Paul, Minn., is charged with espionage, three counts of conspiracy to commit espionage, four counts of failure to obey regulations and five counts of wrongfully disclosing the identity of U.S. personnel in contravention of Article 134 of the Uniform Code of Military Justice.

The maximum penalty for conviction on all counts includes life imprisonment, dishonorable discharge, forfeiture of all pay, and reduction in rank to the lowest pay grade.

The charges all relate to his service as a Marine guard in Moscow between Sept. 27, 1984, and March 10, 1986. Prosecutors allege that as a result of a liaison with Violetta Seina, a woman translator at the U.S. Embassy who was a KGB (Soviet secret police) agent, he handed over classified documents and revealed the identity of U.S. personnel. Much of the prosecution case is based on statements Lonetree made to investigators after he left Moscow and began serving at the U.S. Embassy in Vienna.

In the ensuing probe, the entire 28-man Moscow Marine guard was recalled to the United States for questioning, while high administration figures lamented what they called irreparable damage.

But the investigation has encountered major setbacks. The most serious charges against Lonetree, that he allowed Soviet agents into the U.S. Embassy, have been dropped.

Marine Cpl. Arnold Bracy, originally described by investigators as an accomplice, was cleared of all charges after recanting his confession, saying it had been coerced.

Another Marine assigned to the Moscow embassy at the same time as Lonetree, Sgt. Kenneth J. Kelliher, faces possible court-martial on charges of involvement with Soviet women, dealing in the black market and copying classified documents.

Staff Sgt. Robert S. Stufflebeam faces charges of failing to report his involvement with Soviet women.

Lonetree's father, Spencer Lonetree, who is divorced from his mother, said his son was a "victim of falling in love and being a human being." He added, "I have seen a picture of the woman and she seems very attractive. I cannot blame him for his taste in the beauty of women." He blamed U.S. authorities for allowing Soviets to work in the U.S. Embassy.