Roman Andreye vich Rudenko, 73, the Soviet Union's chief legal officer who served as that country's chief prosecutor at the Nuremberg war crimes trials of 1945-46 and who, in 1960 was chief prosecutor in the espionage trial of U-2 pilot Francis G. (Gary) Powers, died Friday, the Soviet news agency Tass reported on Sunday. The cause of death was not disclosed.

Along with prosecutors from the U.S. France and Britain, Mr. Rudenko led the legal proceedings against Nazi Germany's leaders for their crimes during World War II. He played a major role in preparing the case against Hermann Goering, Albert Speer and Rudolf Hess.

A few months after Stalin's death in 1953, he was named Russia's prosecutor general, reportedly with the assistance of Nikita Khruschev. Earlier, he had served as public prosecutor in the Ukraine for about eight years.

In early 1954, Mr. Rudenko issued the indictment against Secret Police Chief Lavrenti M. Beria, who was accused of using his power against other Soviet leaders, and who later was tried and executed.

Throughout his career, Mr. Rudenko dealt with alleged plots and spying against the state. He was ideologically trusted and elected a candidate member of the Central Committee of the All-Union Communist Party in 1956.

His obituray, signed by leaders of the Communist Party Central Committee, hailed him as an "active participant in communist construction, faithful son of the Soviet people, prominent lawyer."

Particular note was paid by Tass to Mr. Rudenko's work in the post-war reconstruction of the Ukraine following the Nazi occupation.

Westerners described him as a strong party man who skillfully adapted to changes in party policy or leadership.

As prosecutor, or attorney, general, Mr. Rudenko headed the Procuracy, a state agency empowered to prosecute criminal cases and to appoint all republic and local prosecutors. Critics charge that the Procuracy has failed to protect the rights of Soviet citizens against the state.

Mr. Rudenko was born into a peasant family in the small Ukrainian village of Nosovka in 1907. Although educated in the Ukraine, his legal training was unknown.

He joined the Communist Party in 1926, at the start of Stalin's collectivization campaign. By the late 1920s, he was working in the office of the procuracy, which at that time was engaged in seizing land owned by prosperous peasants and needed for the collectives. In the 1930s, when prominent Communist leader from the Ukraine were purged, the procurator's office took part of the trials that condemned these men.

Mr. Rudenko was said to have taken part in, and survived, all of the Soviet purges of that era.

He received several awards, including the Soviet Union's highest civilian decoration, the Order of Lenin.