Rybka's posts relating to the allegations were no longer accessible on Instagram yesterday, but Navalny's 25-minute YouTube video - that has racked up more than five million hits since it was posted last week - was still available.
A Wednesday deadline has been set. If a decision is not reached by the end of today (14 February), Russian internet service providers (ISPs) must take action themselves.
Navalny's LiveJournal blog was blocked in March 2014 along with a number of opposition news websites after demonstrations in Moscow against Russia's annexation of the Crimean peninsula from Ukraine.
Navalny has suggested that he is being targeted due to his calls to boycott the 2018 presidential election, which he calls rigged for Putin. "If you take any of my anti-corruption investigations or any points from my political platform, I'm sure the majority of Russian citizens would support me - and that's why I wasn't allowed to run".
Russia wants videos on YouTube and Instagram showing a senior government official cavorting on a yacht with an oligarch once close to Russian President Vladimir Putin taken down, leaving both companies scrambling to respond.
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Navalny claims the holiday on the billionaire's yacht amounts to a "bribe", and points to a relationship between Deripaska and Manafort, suggesting the two Russians may have been discussing the 2016 United States presidential election.
Deripaska won an order from the Ust-Labinsk court in his native Krasnodar Region ordering the removal of 14 Instagram posts and seven YouTube videos that "breached his right to privacy".
Navalny in trouble with Russian government and Google over video supposedly capturing a hush-hush meeting on a yacht.
But to date, neither it nor Facebook has censored the material. It also demanded that YouTube remove the Navalny clip. The probe draws from the social media account of a woman who claims to have had an affair with Deripaska.
"I will severely suppress any attempts to create and disseminate false information flow using all legal measures and will defend my honour and dignity in court".
In spite of the refusal of big foreign internet companies to share data with the Russian Federation authorities, the FSB says it now has a method to collect encryption keys to spy on users' data, including means to decode to information from Facebook, WhatsApp and Telegram.