Babkin (left) said he had been forced to confess to treason

Rocket scientist Anatoly Babkin, 72, was convicted of espionage despite his claim that he supplied former US naval intelligence officer Edmund Pope only with publicly available documents.

He said the Federal Security Service (FSB) - a successor of the KGB - had forced him to confess to treason under duress.

Mr Pope was sentenced by a Russian court to 20 years of hard labour in December 2000, but was pardoned by President Vladimir Putin a week later because of a chronic cancer condition.

It was analogous to an acquittal Babkin lawyer Viktor Danilchenko

Mr Pope made an impassioned plea in his colleague's defence in an open letter published in the Moscow Times on Wednesday.

"Many in Russia, especially in the scientific community, are suffering under repression in the old/new FSB," he wrote.

Mr Babkin's lawyer, Viktor Danilchenko, said his client's eight-year suspended sentence was a victory of sorts.

Edmond Pope was interested in the Shkval torpedo

"It was analogous to an acquittal, though the judge didn't have the courage to hand down an acquittal," he told Associated Press.

Mr Babkin, was also put on probation for five years, and banned for three years from his post as head of the rocket engine faculty at the Bauman Technical University in Moscow.

He is likely to appeal to the Supreme Court.

The prosecution said Mr Babkin and Mr Pope were gathering secret data on the new Shkval high-speed underwater torpedo.