Moscow, Russia (CNN) -- The remains of Adolf Hitler were burned in 1970 by Soviet KGB agents and thrown into a river in Germany on direct orders from the spy agency's chief, a top Russian security official said this week.

The head archivist of Russia's Federal Security Service (FSB) -- the successor to the former Soviet Union's KGB -- confirmed for the first time the chain of events that led to the disposal of Hitler's body, and who ordered the operation, in an exclusive interview with Russia's Interfax news agency.

Gen. Vasily Khristoforov told Interfax in an interview published Monday that previously secret documents show that KGB chief Yuri Andropov, with prior consent from the Soviet Communist Party leadership, ordered a top secret operation to destroy the remains of Hitler, his wife Eva Braun, Nazi Germany's propaganda chief, Joseph Goebbels; and Goebbels' entire family.

Khristoforov said according to the documents, Andropov's decision to destroy the remains of the Nazi leaders and their family members was motivated by the fears of the KGB and Soviet Communist Party leadership that Hitler's burial site could become a place of worship for supporters of fascist ideas.

Neither the FSB nor Khristoforov were immediately available to comment on the secret documents, when asked by CNN.

The operation, code-named "The Archives," was carried out by a group of special KGB agents in Magdeburg, East Germany, where the bodies had been secretly buried February 21, 1946, on the territory of a Soviet military facility, Khristoforov said.

Two protocols were compiled after the operation was carried out on April 4, 1970, the general said. The first documented the opening of a grave that contained the remains of the Nazi leaders and their family members, and the other one detailed their physical destruction.

"The remains were burnt on a bonfire outside the town of Shoenebeck, 11 kilometers away from Magdeburg, then ground into ashes, collected and thrown into the Biederitz River," the second document reads, according to Khristoforov.

The bodies of Hitler, Braun and the Goebbels family had been discovered by the Soviet Army in May 1945. The bodies of Goebbels and his wife were found May 2 in the garden of Nazi Germany's Reich Chancellery. The bodies of the couple's children were recovered the next day, and the corpses of Hitler and Braun were discovered May 5 in a crater from an artillery shell outside his bunker in Berlin.

According to historical accounts, Hitler's death was a combination of a suicide by gunshot and cyanide poisoning on April 30, 1945, when the Soviet Army entered the Nazi Germany capital.

In early June of that year, the Soviets buried the bodies in a forest near the town of Rathenau, Germany. Eight months later, they secretly re-buried the remains in the Soviet Army's garrison in Magdeburg.

But in March 1970, the Soviets decided to abandon the garrison and pass it over to the East German civilian authorities.

As long as the burial place of the Nazi leaders was in the territory of a Soviet garrison, it could be kept secret and barred from strangers. But following relocation of the Soviet Army unit, the decision was made not to rebury Hitler's remains but to burn them, Khristoforov explained, calling it "perhaps a reasonable decision" given the circumstances.

Khristoforov said that all that remains of Hitler's corpse are fragments of his jawbone and skull, items that are kept in Russia.

The general said the Russian FSB has no doubts that the bone fragments are genuine. No other fragments of the German dictator exist in other countries, he said.

"Hitler's jaw is kept at the FSB archives, and the fragments of Hitler's skull are at the State Archive. There are no other parts of Hitler's body apart from these samples seized on May 5, 1945.

"Everything [else] that remained of Hitler was burnt in 1970," he added. "Those fragments are ... the only documented evidence of Hitler's death, which is why they are kept at the Russian FSB Central Archive as being particularly valuable."

Commenting on recent media reports that archeologist and bone specialist Nick Bellantoni and genetics professor Linda Strausbaugh of the University of Connecticut expressed doubts about the authenticity of the parts of Hitler's skull, Khristoforov said, "The U.S. researchers did not file such requests [for taking DNA samples] with the Russian FSB Central Archive.

"But even if you take the fragments kept in our custody, it is unclear what these data can be compared with."

In April 2000, a fragment of what was presented as Hitler's skull, complete with a bullet hole in it, was first displayed in Moscow at a World War II exhibition.

At the time, Sergei Mironenko, head of the Russian State Archives, told CNN that he is absolutely confident that the skull was authentic, and that there are many documents the Russian archives also put on display along with the skull to support that.

"Those documents provide convincing proof that all those speculations that Hitler could have survived and escaped, that he could have had plastic surgery, are absolutely groundless. He was a totally depressed man who was incapable of making political or any other kinds of decisions. He understood that his bunker, the crater [where he was found dead], would become his last refuge. And that's exactly what happened," Mironenko said.