A Moscow court says it is fining Alphabet's Google 7.2 billion roubles ($A135 million) for what it claims was a repeated failure to delete content Russia deems illegal, the first revenue-based fine of its kind in Russia.
Moscow has increased pressure on big tech this year in a campaign that critics characterise as an attempt by Russian authorities to exert tighter control over the internet, something they say threatens individual and corporate freedom.
Google said in an email it would study the court ruling before deciding on further steps.
Russia has imposed small fines on foreign technology companies throughout this year, but Friday's penalty marks the first time it has exacted a percentage of a company's annual Russian turnover, greatly increasing the sum of the fine.
It did not specify the percentage, although Reuters calculations show it equates to just over 8 per cent.
Russia has ordered companies to delete posts promoting drug abuse and dangerous pastimes, information about homemade weapons and explosives, as well as ones by groups it designates as extremist or terrorist.
Google, which has paid more than 32 million roubles ($A600,000) in fines over content violations this year, is at odds with Moscow on a number of issues.
Russia has demanded it restore access to state-backed broadcaster RT's German-language channels.
Last week, a sanctioned Russian businessman claimed victory over Google in a court case that could see the tech giant hit with another heavy fine.
Moscow has also demanded that 13 foreign and mostly US technology companies, which include Google and Meta Platforms, be set up on Russian soil by January 1 or face possible restrictions or outright bans.