Russian lawmakers on Thursday approved a bill that would allow Moscow to cut the country's internet traffic from foreign servers, in a key second reading paving the way for legislation that activists fear is a step towards online isolation.
Critics call the bill a form of "digital slavery," that threatens censorship and possibly a sealed network similar to that in North Korea.
It is set to take effect on November 1 once it formally becomes law.
The proposed measures would create technology to monitor internet routing and steer Russian internet traffic away from foreign servers, ostensibly to prevent a foreign country from shutting it down.
Lawmakers in the State Duma, parliament's lower house, voted 320 to 15 to pass the bill.
Authors of the initiative say Russia must ensure the security of its networks after US President Donald Trump unveiled a new American cybersecurity strategy last year that said Russia had carried out cyber attacks with impunity.
The legislation has been dubbed the "sovereign internet" bill by Russian media.
Critics say implementing the measures would be expensive and give vast censorship powers to the government's new traffic monitoring centre.
Thousands of people rallied last month against this and other bills that critics say aim at restricting information and communication online.
Last month President Vladimir Putin signed controversial laws that allow courts to fine and briefly jail people for showing disrespect towards authorities, and block media for publishing "fake news".
"It's a bill on digital slavery and the introduction of censorship for the web," said Sergei Ivanov, a member of the nationalist Liberal-Democratic Party.
"I've never seen such a blatant and cynical bill which is being pushed through like this amid claims that not a penny will be spent from the budget," he added.
Russian business news website RBK reported in March that implementing the measures would cost an estimated 30 billion rubles ($466 million).
The bill's authors insist that the measures only outline a plan to make Russian internet "more secure and reliable".
"The bill's popular name -- 'The Chinese Firewall' -- has nothing to do with our initiative," said Leonid Levin, a lawmaker from the ruling United Russia party which dominates Russian parliament.
Levin said that ahead of the second reading lawmakers had looked through 58 proposed amendments and that the legislation included comments from critics and industry experts.
"Significant work had been done," he added.
Internet activist Artyom Kozlyuk said however the amended text was even more vague than the previous version and "did not change for the better."
Kozlyuk, who coordinates the Roscomsvoboda anti-censorship organisation, added the bill had been sailing through parliament "very quickly" despite pleas from the public and the communications industry to pause and have a proper discussion.
While it would be technically difficult to completely cut off Russia from the world wide web, if the bill passes, "it will create serious economic risks for the industry and for the country," Kozlyuk added.
The bill is set to take effect after a third reading in the State Duma and a vote in the upper house, both of which are seen as a formality.
Then the bill would be formally signed into law by Putin.
The Kremlin insisted it has no desire to isolate Russian internet users.
"No one is suggesting cutting the internet," spokesman Dmitry Peskov has said, adding that the protesters suffered from "delusions."