POLICE yesterday detained 20 activists protesting outside Russia's parliament where deputies debated a Kremlin-backed bill to hike fines for violations during rallies.

The controversial bill, which the opposition says is aimed at smothering dissent, follows the biggest protests of President Vladimir Putin's 12-year rule and is all but guaranteed to be passed this week by the State Duma lower house, where United Russia holds a majority.

It would raise maximum fines to one million roubles (£19,660) for organisers and 300,000 roubles (£5900) for citizens participating in demonstrations at which public order or city rules are deemed to have been violated.

Opposition politicians proposed more than 350 amendments to delay a bill they say is being fast-tracked by the Kremlin before a planned mass protest in the capital on June 12.

"This is a monstrous bill which will essentially ban people from protesting," Sergei Mitrokhin, an opposition leader whose party has no seats in parliament, said. Moments later, he was detained with other activists, many wearing the white-ribbon symbol of the anti-Putin movement.

Some of the most controversial proposals, such as fines for internet users who spread the word about rallies, have been dropped. But Kremlin critics say the proposals remain draconian.