Police cart away demonstrators outside Russia's parliament.

They're protesting to save the right to free assembly.

Under threat -- they say -- from a new law which will ramp up fines for unathorised gatherings.

Proposed by the ruling United Russia party, it's part of a crackdown on unrest fueled by suspicions of election fraud and anger at President Vladmir Putin.

The party is pushing the bill through the lower house despite opposition from all other parties in the State Duma.

One lawmaker says it will only increase conflicts.

(SOUNDBITE) (Russian) 'A JUST RUSSIA' PARTY PARLIAMENT FACTION MEMBER GENNADY GUDKOV SAYING:

"Today, I would like to stress it again, Article 31 of the Russian Constitution (guaranteeing freedom of assembly) will be finally destroyed. It's happening when tension in society is growing in strength, when people's activity is growing and this is an obvious attempt to drive the protest underground or into a corner, but we know how it usually ends."

The proposal would dramatically increase fines up to 48,000 U.S. dollars for protest organisers and 32,000 for participants.

Lindsey Parietti, Reuters