After protests, Russian watchdog says entities bought ad tools to spread information about unsanctioned demonstrations.

Tens of thousands of people on Saturday staged what observers called the country's biggest political protest in years, defying a crackdown to demand free elections for the legislature of the capital, Moscow.

Multiple YouTube channels broadcast the event live. Some videos attracted more than 50,000 people according to organisers. In contrast to previous protests, the authorities had approved this rally.

Roscomnadzor, the watchdog, said on Sunday it had written a letter to Google in which it noted that some entities had been buying advertising tools from YouTube, such as push notifications, to spread information about unsanctioned protests, including those aimed at disrupting elections.

It said Russia would consider a failure by Google to respond to the request as "interference in its sovereign affairs" and "hostile influence (over) and obstruction of democratic elections in Russia".

If the company does not take measures to prevent events from being promoted on its platforms, Russia reserves the right to respond accordingly, Roscomnadzor said in its statement, without giving details.

Tougher laws:

Over the past five years, Russia has introduced tougher laws requiring search engines to delete some search results, messaging services to share encryption keys with security services and social networks to store Russian users' personal data on servers within the country.

There was no immediate comment from Google.

Moscow has a track record of putting regulatory pressure on Google, one of the main rivals of Russian internet search company Yandex.

In late 2018, Russia fined Google 500,000 roubles ($7,663) for failing to comply with a legal requirement to remove certain entries from its search results.

Earlier that year, Google removed a YouTube advertisement by Russian opposition leader Alexei Navalny after authorities complained that the videos violated a law prohibiting campaigning before a vote for regional governors.