A bill which massively increases the size of fines for unapproved rallies in Russia has begun its passage through parliament amid strong protests.
MPs from President Vladimir Putin's United Russia party passed the bill in its first reading by a majority of 236 to 207 in the State Duma.
Rally organisers could face maximum fines of 1.5m roubles (£30,000; $48,000), up from 50,000 roubles.
Critics accused the ruling party of destroying democratic freedoms.
Sergei Mironov, leader of the opposition A Just Russia, said his party was boycotting the parliamentary readings. He said the "odious" bill was intended to "shut the people's mouth".
The giant anti-government demonstrations in Moscow which followed parliamentary elections in December were approved by the authorities in advance.
However, unauthorised spontaneous protests have been held since Mr Putin's inauguration as president for the third time on 7 May, and demonstrators have clashed with police.
In another development, Mr Putin appointed the outgoing Interior Minister, Rashid Nurgaliyev, as a presidential adviser.
The new Russian cabinet announced on Monday retained many of the previous government's ministers.
Under the new bill, anyone who "allows illegal activities during the preparation and conduct of mass actions" risks being fined.
While organisers face a maximum fine of 1.5m roubles, ordinary participants also risk a substantial fine of 1m roubles (£20,000; $32,000).
It is expected that the sums will be reduced by about two-thirds in time for the bill's second reading, but protesters would still risk a maximum fine of roughly the average annual salary in Russia.
Police arrested several members of the liberal opposition party Yabloko as they attempted to protest against the new bill outside parliament.
Yabloko leader Sergei Mitrokhin told reporters before being detained: "A direct signal is being made by those in power: sit down and keep quiet!"
"Using the May 6 and 7 protests as an excuse, United Russia is attacking the last of our more or less functioning democratic rights," Communist Party lawmaker Vadim Solovyov said on Tuesday.