A new Russian internet law came into effect on November 1 that lawmakers say is designed to protect the country's internet "Runet" in case of a cyber-attack or other external threat.
The "sovereign internet" law would allow the country's telecommunications body Roskomnadzor to isolate the Runet from the global network in the event of an attack.
The head of Roskomnadzor, Alexander Zharov, has said that they would only resort to blocking the internet or certain providers in an emergency.
Critics say the law will allow the government to increase internet censorship.
"Now the government can directly censor content or even turn Russia’s internet into a closed system without telling the public what they are doing or why," said Rachel Denber, deputy Europe and Central Asia director at Human Rights Watch, in a statement.
"This jeopardizes the right of people in Russia to free speech and freedom of information online."
The law requires special equipment to be installed by internet providers which could filter and reroute traffic, and restrict access to illegal information.
The law has entered into force, but the new equipment is not yet completed.
The cost of implementing the law will amount to more than 30 billion rubles (€424 million), of which 20.8 billion rubles (€294 million) will be spent on purchasing equipment.
Anton Fishman, a project director at cybersecurity firm Group-IB, said the law is justified.
"Given the tense geopolitical situation and possible risks from other countries, this law is provided just for preliminary protection against possible risk," Fishman said.
'A new level' of censorship
But Christian Mihr, the executive director of Reporters Without Borders in Germany, said that it takes internet censorship to a new level.
"It proves that the Russian leadership is ready to bring the entire network infrastructure under political control in order to cut off the digital information flow whenever needed," Mihr said in a statement.
Russian digital rights NGO RosKomSvoboda that the law could increase internet blackouts. The group's lawyer, Sarkis Darbinyan said that although there is a growing cyber threat, the law will not make Russia's internet safer.
Darbinyan also said that it did not guarantee freedom of information, freedom of expression or protection of privacy.
The law does not specify which threats would bring the Runet under centralised control.