A Russian court on Tuesday (September 14) said it had fined U.S. social media giants Facebook and Twitter for failing to delete content that Moscow deems illegal.

The move forms part of a wider crackdown on the sector.

Moscow wants foreign big tech firms to open full-fledged offices in Russia.

And to store Russians' personal data on its territory.

The government also published plans on Tuesday to impose new taxes on foreign-owned digital services as part of a push to support its domestic tech sector.

The court said Facebook had been handed five fines totalling 21 million roubles, or almost $288,000.

Twitter received two fines.

While popular messaging app Telegram was also penalised.

Facebook, Twitter and Telegram did not immediately respond to requests for comment.

Twitter has been the subject of a punitive slowdown since March.

Russia says Twitter and other social media firms have not deleted posts featuring banned material quickly enough.