Russian lawmakers have approved in its first reading a bill that would dramatically boost fines on protesters.
The draft law, backed by the pro-Kremlin United Russia party, proposes fines of up to 1.5 million rubles ($48,000) per detained demonstrator found guilty of violating legislation governing street rallies.
The initiative has been condemned by opposition supporters, who say it could threaten the survival of their public protest movement against President Vladimir Putin.
The three opposition parties at the State Duma lower house of parliament, which generally follow United Russia's lead, voted against the bill, which passed in its initial reading with 236 in favor, 207 opposed, and one abstention.
"We have not supported this law and we cannot support it," Communist leader Gennady Zyuganov said ahead of the vote. "Fines of up 1.5 million rubles have been introduced for the slightest sneeze or cough."
Sergei Mironov, the leader of the A Just Russia party, said the new fines were designed to crush dissent.
"Why was there a need to increase the fines by 1,500 times?" he asked. "The answer is clear: to intimidate those ready to take part in civic protests."
Liberal Democratic Party of Vladimir Zhirinovsky said it did not oppose the fines but maintained that the proposed amounts were too high.
A number of opponents of the bill, including Yabloko party leader Sergei Mitrokhin, were detained on May 22 as they protested its first reading outside the State Duma.
The demonstrators had hoped their presence outside the building would persuade deputies to reconsider adopting the bill.
'A Disgraceful Event'
Mitrokhin said that the protesters wanted to convince deputies who were passing that they should refrain from "mocking Russian citizens."
"We hope we can disrupt this disgraceful event planned today," Mitrokhin told reporters.
Russia's opposition has staged a series of unprecedented mass rallies against Putin's continued rule, including protracted sit-ins and protest walks, since last December's parliamentary polls, which were marred by allegations of fraud.
Putin has ruled Russia as president or prime minister for the past 12 years.
In recent weeks, a number of opposition figures have been detained and fined for taking part in the protests.
Three of them, Aleksei Navalny, Sergei Udaltsov, and Ilya Yashin, have been handed jail sentences of up to 15 days on charges of disobeying the police.
The bill's first reading was initially scheduled for May 18, but was postponed after opposition deputies threatened to boycott the session.
Advocates of the draft law have since raised the possibility that the amount of the fines could be reduced before the bill faces a second reading in the Duma.
The bill's authors say they also plan to add further restrictions on street protests before the second reading. These would include barring individuals who have a criminal record or were sentenced more than twice to administrative arrest from organizing rallies.
They hope to adopt the draft law in a third reading by the beginning of June.
The bill would then be sent to the upper legislative chamber, the Federation Council, for approval before being sent to the president for signature.
With reporting by Reuters