A Russian physicist acquitted of spying for China is to be re-tried.
Danilov was accused of passing on secrets of Russia's space industry
Valentin Danilov was cleared in December of passing on space technology secrets - but the Russian supreme court has overturned the verdict.
The BBC's correspondent Steve Rosenberg says the original acquittal was widely seen as a defeat for Russia's intelligence service, the FSB.
Several scientists and researchers have been tried for spying recently - and most have been convicted.
Mr Danilov, a professor at Krasnoyarsk Technical
University in Siberia, said at his three-year trial that information he sold to a Chinese organisation was already in the public domain.
But prosecutors alleged that jurors were put under pressure during the case.
A supreme court spokesman said violations had been found and that the case would be sent back to the Krasnoyarsk
court for a new trial with different judges.
Mr Danilov, the 53-year-old former head of his university's space research laboratory, said the decision "could have been expected".
But he said the charges and evidence had not
changed and he said he was confident that the result would be "one and the same".
Human rights groups accuse the Russian security services of using KGB-era tactics to target scientists and researchers who have established links with foreign organisations:
- In April, weapons expert Igor Sutyagin was jailed for 15 years for spying for the US while working for Russia's USA-Canada institute
- Last December, former intelligence officer Alexander
Zaporozhsky's 18-years'-hard-labour sentence for spying for the US was upheld
- Last year, 72-year-old professor Anatoly Babkin was
given an eight-year suspended sentence for passing secret information to US businessman Edmond Pope