Ronald W. Pelton began his career as a spy for the Soviets with an anonymous phone call six years ago to the Soviet Embassy in Washington, according to court papers filed by the government yesterday.

On Jan. 14, 1980, Pelton, a former communications specialist at the highly secret National Security Agency, called the embassy and told an official there he had "information to discuss" that the Soviets would find "very interesting," according to documents filed in federal court here.

The documents, which cite a tape recording of the conversation, say Pelton was invited to the embassy for a private talk the following day after he declined to discuss his information over the phone.

That afternoon, Pelton met with officials at the embassy for 3 1/2 hours and told them of a location from which they were losing intelligence information to the United States, prosecutors said. As proof of his identity, he showed the Soviets a photograph of an NSA training class and his certificate of completion of the class, according to the documents.

The government alleges that details of what transpired at that meeting came from Pelton himself during interviews with FBI agents shortly before his arrest Nov. 24 in Annapolis. Pelton allegedly told the FBI that he took no classified documents with him when he first met with Soviet officials.

Pelton, 44, who had clearance for top secret materials and even more highly classified information during his 14 years at NSA, is accused of selling the Soviets "extremely sensitive" information about U.S. intelligence-gathering operations directed at the Soviet Union. He is alleged to have spied for the Soviets from 1980, the year after he left NSA, until he was arrested by FBI agents last fall.

In court papers filed previously, prosecutors alleged that Pelton was "incidently overheard" and recorded on a government wiretap in January 1980. They have also asserted that evidence against Pelton includes a taped conversation with Vitaly Yurchenko, the turnabout Soviet defector who was the KGB's security officer at the embassy until May 1980.

The FBI has said previously that information provided by Yurchenko last fall led to Pelton's arrest.

The government filed the documents yesterday in an effort to establish that Pelton's alleged espionage activities began in Maryland and that U.S. District Court here is the proper venue for the case.

At one point in the first taped conversation with the Soviet Embassy official, Pelton allegedly said it would take him a half-hour or longer to get to the embassy. Prosecutors say this suggests that he was at home or at work in Maryland when he allegedly made the call.