President Vladimir Putin has signed a law redefining treason in Russia amid fears it may be used to stifle dissent.
Now not only Russians working for foreign intelligence can be convicted but also citizens who pass state secrets to any foreign organisation.
Even if no secrets have been divulged, the treason charge may still be used.
It is enough for defendants to provide consultancy or "other assistance" to a foreign state or international body "directed against Russia's security".
The maximum punishment for high treason remains 20 years in prison but under the changes, Russians can now be jailed for up to four years if they have obtained state secrets - even if they have not shared them.
They can be jailed for up to eight years if they obtain them with the help of special surveillance equipment.
Human rights campaigners believe the aim of the legislation is to scare Russians into cutting links with Western non-governmental organisations, the BBC's Steve Rosenberg reports from Moscow.
Academic to be freed
Earlier this week, President Putin told his own human rights council that foreign influence on domestic politics was unacceptable and that Russia should not allow anyone from abroad to influence it by stealth, by providing finance.
He had promised to review the treason law but now he has signed it, our correspondent says.
The issue of what does or does not constitute treason re-emerged on Tuesday when it was announced that a physicist convicted in 2004 of spying for China would have his prison sentence reduced.
A court cut Valentin Danilov's 14-year sentence by three years on grounds of good behaviour and the state of his health.
He is due to be released on parole from his prison in Krasnoyarsk, western Siberia, within nine days.
First arrested in 2001, Danilov admitted selling information about satellite technology to a Chinese company but said the information was already available from public sources.
Human rights campaigners saw his arrest as an attempt to intimidate academics with ties to other countries.