Russian scientist arrested in espionage probe: agencies

The Roscosmos space organisation confirmed in comments to agencies that 74-year-old Viktor Kudryavtsev from the Central Research Institute of Machine Building near Moscow had been detained.

Award-winning scientist Kudryavtsev insisted he was not guilty of treason, his son said in reported comments.

Roscosmos denied reports a second employee of the research institute had been arrested.

Russia's FSB security services last week raided the institute on the basis that Western security services had obtained information on secret hypersonic developments by Russian industry.

Sources told the Kommersant newspaper the probe was over "high treason," with around 10 people suspected of "cooperation with Western secret services."

The Russian space agency confirmed an investigation was taking place, saying it was looking at events in 2013.

The probe comes after President Vladimir Putin in March boasted in a state-of-the-nation address of new "invincible" weapons under development, including hypersonic missiles.