A federal grand jury indicted accused father-son spy team John and Michael Walker today on charges of conspiring with the vice consul at the Soviet Embassy in Washington to supply classified information to the Soviet Union.

The six-count indictment, handed down in federal court here, charges the Walkers with conspiring to funnel secrets to Aleksey Gavrilovich Tkachenko from sometime after April 1983 through last week.

Yuri Popov, third secretary at the Soviet Embassy in Washington, said today he could not comment on the case, but added that he might have a statement later.

Official sources said last week that a Soviet national connected with the incident had left the country.

The indictment alleges that Navy seaman Michael Lance Walker, 22, gathered documents related to national defense and gave them to his father, who then attempted to deliver them to a Soviet agent. Both Walkers were compensated for their roles, the indictment charges.

As part of that conspiracy, the indictment alleges, Michael Walker took a document classified "secret" from the Oceana Naval Air Station in Virginia Beach when he was assigned to a fighter squadron there in late 1983. The indictment alleges that in March 1984, Walker received $1,000 in return for classified documents he had taken from the air station.

The indictment did not mention any other specific incidents in which either Walker allegedly took classified documents and gave no indication of how much money they allegedly received.

Until his arrest last week, Walker was a seaman aboard the nuclear aircraft carrier U.S.S. Nimitz. His father, John A. Walker Jr., 47, a Norfolk private detective, retired from the Navy in 1976 after a 21-year career.

Both Walkers are charged with conspiracy to deliver to the Soviet Union documents relating to the national defense with the intent of injuring the United States, and with attempting the delivery of those documents earlier this month.

The charges carry maximum penalties of life in prison.

Both also are charged with attempting to deliver national defense-related documents to Tkachenko. Michael Walker is charged with unauthorized possession of national defense information, and his father is charged with receiving such information from his son knowing the information had been taken illegally.

Each of those charges carries a maximum penalty of 10 years in prison and a $10,000 fine.

A government agent testified in court last week that John Walker, who had a "top secret crypto" clearance while in the Navy, may have been spying for the Soviet Union for as long as 18 years. But the indictment alleges only that the conspiracy began "on a date unknown to the Grand Jury but after April 1983."

Both Walkers were arrested last week after FBI agents saw John Walker deposit a bag filled with 129 classified documents in a wooded area in western Montgomery County, according to an affidavit filed in federal court here. The affidavit states that a Soviet national was seen in the vicinity of the alleged "drop site."

Before the indictment today, Michael Walker made an initial appearance before a federal magistrate, who informed him of the charges against him and of his constitutional rights. A bond hearing is set for Wednesday.

Wearing a blue work shirt and blue jeans, Walker answered quietly "Yes, your honor," when Magistrate Daniel E. Klein Jr. asked if he understood that the charges against him could mean life in prison.

Klein appointed lawyer Charles G. Bernstein to represent Walker. Walker's wife of 18 months, Rachel Sara Allen Walker, tried to catch her husband's eye when he walked handcuffed into the hearing room, which was jammed with reporters.

Accompanied by her father, Rachel Walker fiddled nervously with her wedding band and engagement ring as she waited for the hearing to start. At the end of the brief hearing, she ran up to the low partition separating the courtroom spectators from the lawyers, called her husband's name and began to cry.

Later, she showed reporters a porcelain figurine of a mermaid she said Michael Walker had bought for his mother, Barbara. Barbara Walker and a daughter turned John and Michael Walker in to federal authorities, according to law enforcement sources.

John Walker is being held without bond in the Baltimore City Jail. Authorities will not say where Michael Walker is being held.

A financial disclosure form filed by Michael Walker in order to have an attorney appointed to represent him showed his only asset to be a car valued at $10,000. The form states that Walker earns $900 monthly on the Nimitz, and that his wife, a lab technician, earns $400 monthly.

John Walker's financial form states that he earns $1,000 a month from his detective business, and an additional $12,000 annually from his military pension. The form lists savings of $1,150; his Norfolk home, worth $70,000; a lot in Norfolk valued at $60,000; four acres in Ladson, S.C., worth $60,000; and a 1980 Chrysler worth $6,000.

John Walker listed his debts as $35,000 on his home, $10,000 on the land in South Carolina and $1,200 in charge card expenses.

FBI officials have said they believe the Walkers' motivations for the alleged spying were financial, and that agents have been searching for bank accounts and other assets.