The Russian lower house or State Duma early Wednesday adopted a controversial bill that would greatly increase fines for protesters.
An opposition party had earlier deliberately stalled the passing of the bill by calling for votes on hundreds of amendments. It was finally passed at the third reading by 241-147 and was to be sent upstairs to the Federation Council before ratification by President Vladimir Putin.
In a highly unusual spectacle in the usually rubber-stamp parliament, A Just Russia party submitted more than 400 amendments to the bill in its crucial second reading and then insisted on reading out each one in detail.
The parliament's lower house is dominated by ruling party United Russia, which had enough votes to shoe-in the bill, although numerous members were absent on Tuesday and their colleagues were pushing buttons for them.
The controversial bill would hike the maximum penalty for organisers of illegal protests to one million rubles ($32,100), while participants could be fined up to 300,000 rubles ($9,000).
Human Rights Watch criticised the bill, saying the measures "would severely undercut the right to peaceful assembly".
During the debate, Gennady Gudkov of A Just Russia criticised what he called "inordinate" fines, which he said "not one normal person can pay without destroying the family budget".
The bill was hastily submitted less than a month ago and passed in its first reading on May 22.
It allows authorities to punish de facto organisers of informal "walking protests" that have been recently used by the opposition, under the vague definition of "being en masse simultaneously".
The maximum penalty is about 3.5 times the average annual salary reported by the Rosstat statistics agency at the end of last year. Previously, the maximum fine for individual protesters was 5,000 rubles.
The upper house, the Federation Council, even listed the bill on its agenda for Wednesday -- assuming it would have been passed in both its second and third readings in the lower house.
The aim of the failed delaying tactics, or filibustering, was to force parliament to postpone its vote on the bill.
In Russian, the tactic is known as an "Italian strike".
"The Italian strike going on in the State Duma is the coolest thing," protest leader Alexei Navalny wrote on Twitter.
At one point, Ilya Ponomaryov of A Just Russia simply read out numbers of the proposed amendments monotonously, televised on a national channel.
Outside parliament, around 20 opposition demonstrators were detained Tuesday morning protesting against the bill, including Sergei Mitrokhin, the head of liberal Yabloko party, police said, cited by Interfax news agency.
"I see this as an illustration of police lawlessness," Mitrokhin told the Moscow Echo radio station.
Prime Minister Dmitry Medvedev, who heads the United Russia party, tentatively approved the bill in a televised interview late Monday, saying higher fines were needed as a deterrent.
"Do we need huge fines? Huge ones, no, higher ones, yes," he said in a rare live interview. "Because if you break a rule one day, then the next day you pay 500 rubles and do the same thing, this is unacceptable."