A new law broadening the definition of treason was introduced yesterday, alarming opponents of President Vladimir Putin who say it will be used to silence his critics and that almost anyone in contact with foreigners will be at risk.
The legislation allows Russians representing international organisations to be charged with treason, as well as those working for foreign states and bodies, and expands the range of actions that can be considered treasonous.
Political opponents and rights activists say the legislation is the latest in a series of laws intended to crack down on the opposition and reduce foreign influence since Mr Putin returned to the Kremlin in May for a third six-year term.
Lyudmila Alexeyeva, 85, a former Soviet dissident and veteran human rights activist, said: "It's an attempt to return not just to Soviet times but to the Stalin era, when any conversation with a foreigner was seen as a potential threat to the state."
She said it would probably be used selectively against the Kremlin's critics and others "who irritate the authorities".
The Federal Security Service, in a rare public comment, was quoted by the state-run news agency Itar-Tass as saying the law had been updated after being unchanged since the 1960s because "foreign intelligence agencies' methods and tactics for gathering information have changed".