The Russian government is pushing a bill through parliament that critics say would give the country's main intelligence agency, the FSB, powers similar to those once held by its Soviet predecessor, the KGB.

At the time, almost all opponents of the communist regime were ruthlessly silenced.

The bill has been described by Russia's top human rights official as one of the most dangerous pieces of legislation to be put before parliament - but the government says it is needed to tackle extremism.

Even now, holding anti-government protests is extremely risky for opposition groups.

One rally in Moscow on 31 May - like so many others before - was soon broken up by riot police, who arrested more than 150 people.

But if parliament passes the legislation now before it, increasing the powers of the FSB, then opposition activists may not even be able to leave their homes to take part in protests.

'Preventative terror'
The FSB would be able to summon individuals in advance for questioning, and warn them against what it calls extremist activity and the possibility of committing a crime.

If the warning is ignored it could lead to 15 days' detention....