A Moscow court has fined Google 21 billion rubles ($360 million) for failing to remove content concerning Russia's military intervention in Ukraine, the nation's telecommunications regulator said Monday.

Roskomnadzor said the Google-owned video platform YouTube had failed to block "false information" on the offensive in Ukraine, "extremist and terrorist propaganda" and content "calling on minors to participate in unauthorised demonstrations".

The regulator said that as this was a repeat conviction for Google the fine was based on its annual revenue in Russia.

Russian authorities have been dialling up their pressure on Western social media firms in recent years with repeated fines and threats in a bid to remove criticism from the internet, one of the last bastions of free speech in Russia.

Like most of its Western rivals, Google recently quit the Russian market to denounce Russia's military intervention in Ukraine.

According to Vladimir Zykov, an expert cited by Russian news agency Ria-Novosti, the fine is the largest ever imposed on a Western tech firm by a Russian court.

Russian authorities can impose on Google "as many fines as they wish, they won't receive the money" as the firm has pulled out of the country, he added.

Google had no immediate comment concerning the fine.

Roskomnadzor branded the activities of Google and YouTube with the "terrorist" label in March, opening up the possibility they would be blocked in Russia, as have Twitter, Instagram and many independent medias following the start of the military operation.

Russian authorities have increased the legal penalties for speaking out against the conflict. Those found guilty of spreading "false information" about the Russian military face up to 15 years in jail. 

Several people have already been jailed on such charges.