Alger Hiss, the State Department official imprisoned in one of America's most notorious spy scandals, never worked for the Soviet Union, according to Russia's most knowledgeable expert on the KGB archives.


"I have not a single document to show that Hiss was a paid agent", General Dmitry Volkogonov, an advisor to President Yeltsin, told CNN Thursday. "They sent him to jail for nothing; he wasn't a spy".


Volkogonov has access to the Soviet Union's most secret documents, and has publicized a number of surprising revelations over the past few months.


Hiss was accused of passing secret documents to Whittaker Chambers, an editor at Time Magazine, as part of a Soviet-sponsored spy plot in 1948. He was sentenced to five years imprisonment in 1950 for perjury, and he has maintained his innocence ever since.


At a press conference in a New York hotel on Thursday, a frail and shaky Hiss, described "elation, happiness, and joy" at hearing Volkogonov's remarks. A interview with Volkogonov filmed on Oct. 15 by filmmaker John Lowenthal was aired at the press conference.


"To day I'm so happy to have this evidence that I did not have reason to believe was available", Hiss, 87, said in a hoarse voice. "I was never able, despite all the material assembled and the able counsel, to get full vindication".


"I have been sustained by the belief that eventually the truth could come put", he said.


The Hiss case emerged shortly after the Soviet Union had installed puppet governments across Eastern Europe and a "Red Scare" had overtaken American politics.


The publicity around the case helped build the career of a young Congressman from California, Richard Nixon, who served on the House Un-American Activities Committee.


Hiss dodged a question on Thursday about whether Richard Nixon owed him an apology.


"You'll have to ask Mr. Nixon that", he said.


He did say that he felt no "special bitterness" toward Chambers, who died in 1961, although he called him mentally unstable.


In the years since his imprisonment, Hiss has practiced law and has given occasional university lectures on the start of the Cold War.