Alphabet's Google was fined 21.8 billion roubles (€382 million) on Monday by a Russian court for a repeated failure to remove content that Moscow deems illegal, the Interfax news agency reported.
Russia has long objected to foreign tech platforms' distribution of content that falls foul of its restrictions, but what had been a simmering dispute has erupted into a full-on battle since Moscow assembled its armed forces before sending them into Ukraine in February.
Late last year, Google was fined 7.2 billion roubles for failing to remove or block content.
Its Russian unit's bank account has been seized, prompting the subsidiary to file for bankruptcy and making it impossible to pay staff and vendors.
Google, which may appeal the ruling, did not immediately respond to an emailed request for comment.
The communications regulator Roskomnadzor said in June that Alphabet's video platform YouTube was deliberately spreading false information about the conflict in Ukraine, and had permitted content promoting extremist views and calls for children to participate in unauthorised protests.
"The video hosting site YouTube deliberately promotes the dissemination of misleading information about the progress of the special military operation in Ukraine, discrediting the armed forces of the Russian Federation," Roskomnadzor said.
Russia says it is conducting a "special military operation" in Ukraine to defuse a threat to its security and protect Russian speakers from persecution.
Ukraine and its Western allies dismiss such allegations as baseless pretexts for an illegal land grab.
+Additional reporting Reuters