Russian underground opposition leader Alexei Navalny blasted Instagram for caving in to Kremlin censorship on Thursday, adding fresh controversy to the raging battle for control over the internet and social media ahead of Russia’s presidential election next month.

Instagram and YouTube have been caught in a tug-of-war between Russia’s underground opposition and the government in which regulators have threatened to effectively block both services inside Russia if they don’t remove content related to an incendiary investigative video posted online by Navalny last week.

On Thursday, Instagram, which is owned by Facebook, appeared to yield to a Russian court order to remove two posts related to the dispute as ordered by the regulator. Navalny accused Instagram of capitulating to Kremlin pressure.

“Shame on you, @instagram!,” Navalny tweeted. “@instagram decided to comply with Russian illegal censorship requests and deleted some content.”

Neither Instagram nor Facebook immediately responded to requests for comment from VICE News.

Navalny’s own website was also blocked Thursday in the dispute. The Russian regulator, Roskomnadzor, said it’s still waiting for a response from YouTube, and that it is “hoping for a positive decision by Google,” the platform’s parent company, Russian media reported Thursday.

The latest censorship uproar in Russia began last week after Navalny posted a 25-minute-long investigative video alleging that a powerful Russian oligarch named Oleg Deripaska effectively bribed a senior government official by entertaining him on a lavish three-day yacht cruise off the coast of Norway in the company of multiple women from the “escort services.” Navalny also suggested, without providing any substantive proof, that during the August, 2016 trip, the two men may have discussed the then ongoing U.S. presidential election campaign.

To present his case, Navalny drew heavily on content pulled from the flamboyant and provocative Instagram account of a young woman who goes by the name Nastya Rybka, who had posted pictures of herself with Deripaska on the yacht and a video of herself claiming to have had a “relationship” with him.

The oligarch, Deripaska, filed suit last week in a regional court to have the YouTube and Instagram posts blocked, winning a preliminary injunction. Russia’s regulator, Roskomnadzor, then gave both services until February 14 to comply — or face having their services effectively blocked in Russia, because, according to web experts, Russian Internet Service Providers would not be able to simply block individual posts piecemeal.

On Thursday, Russian media regulator, Roskomnadzor, claimed partial victory, telling Russian media that Instagram had voluntarily pulled two posts related to the dispute.

Navalny has been known for his slick investigative videos alleging corruption at Russia’s highest levels, targeting the likes of Russian Prime Minister Dmitry Medvedev and Prosecutor General Yury Chaika. Barred from appearing on state-owned television, Navalny has sought to promote a boycott of Russia’s 2018 presidential election via social media, especially YouTube.

Analysts have said that losing access to YouTube would represent a serious blow to Navalny’s efforts to rally opponents of Russian President Vladimir Putin.

Now, Facebook and Google have been drawn into the center of the dispute between Navalny and the Kremlin, and the Russian government is ramping up pressure on the social media giants.

On Thursday, the same day that Navalny’s video appeared online, the Russian media regulator, Roskomnadzor, announced it held a meeting with Facebook senior staff in Moscow. At the meeting, the regulator informed those executives that it would be carrying out an inspection later in 2018 to make sure Facebook’s operations correspond with Russian law.

Not everyone involved in the feud seemed to be outraged by Instagram’s decision, however.

Rybka, for her part, seemed to revel in the chaos, boasting on Thursday that her own Instagram account had become “the most popular in the Russian Federation” as a result of her role, and posting ruminations on feminism and her own potential future career in pornography. After the regulator ruled the posts be removed, she pulled some of them, then asked her more than 90,000 Instagram followers to vote on whether she should delete the rest. After a majority voted “no,” she left them up.