MOSCOW – The Russian government said Wednesday that it is slowing access to Twitter, accusing the social network of failing to remove illegal content and signaling that the Kremlin is escalating its offensive against American internet companies that have long been a haven for free expression Offer.

Shortly after the announcement, Twitter was still accessible in the country, but dozens of Russian government websites went offline for about an hour, including the website of the Kremlin, Parliament, several ministries and law enforcement agencies. Russian officials blamed a device failure, saying the failure had nothing to do with crackdown on Twitter.

US government officials said over the weekend they were seeking revenge against Russia for a massive hacking attack last year that exploited vulnerabilities in government and corporate computer systems in the US.

Officials said the retaliation was planned in the coming weeks but it remained unclear on Wednesday whether the failure of government websites was a sign of the latest volley in that cyber conflict or an unrelated glitch on the Russian internet.

The Ministry of Digital Development, Communications and Mass Media said in a statement that the problem with government sites was due to a device failure at a state telephone company and internet service provider, Rostelkom, and that it had nothing to do with the separate move by regulators to to slow down traffic on Twitter.

The Russian agency made the announcement in a Twitter post.

Russia’s telecommunications regulator said it was reducing the speed at which Twitter loads for internet users in Russia, although it wasn’t immediately clear how noticeable the move would be. The regulatory authority Roskomnadzor, whose website went offline on Wednesday after the Twitter action was announced, accused the American company of not removing posts about illegal drug use or child pornography or messages that “urge minors to commit suicide” for years.

“With the aim of protecting Russian citizens and forcing the Internet service to comply with the law on the territory of the Russian Federation, centralized reactive measures were taken against Twitter from March 10, 2021 – in particular, the initial throttling of the speed of the service in accordance with the regulations, “said the regulator in a statement.

“If the Internet service Twitter continues to ignore the requirements of the law, the measures against it will continue in accordance with the regulations, up to and including the suspension,” he added.

Twitter did not immediately comment.

The social network has a relatively small reach in Russia, but the approach could have far-reaching implications. Even when President Vladimir V. Putin pushed back democratic freedoms and dampened independent media, he allowed the Internet to remain essentially free.

Twitter – and to a much greater extent Facebook’s Instagram and Google’s YouTube – have given Russians the opportunity to speak, report, and organize openly despite the Kremlin controlling the television waves.

These social networks, along with Chinese-owned TikTok, played a crucial role in the anti-Kremlin protests that accompanied the return and imprisonment of opposition leader Aleksei A. Navalny that year. Mr Navalny has around 2.5 million Twitter followers, and his investigation into an allegedly secret palace of Mr Putin, published in January, has been viewed more than 100 million times on YouTube.

Russian officials claim that Silicon Valley companies are discriminating against Russians by blocking some Kremlin-friendly accounts and handing a megaphone to Kremlin’s critics. They also said that social networks have refused to remove content that dragged children into the unauthorized protests in support of Mr Navalny.

In the past few weeks, the Kremlin has spearheaded an intensified drum beat criticizing American internet companies, calling them corrupt foreign forces.

“Online we encounter child pornography and child prostitution, with the sale and distribution of drugs, targeting children and young people,” Putin said this month.

The Internet, Putin said, “has to respect the moral laws of the society in which we live – otherwise this society will be destroyed from within”.

Twitter has a small user base in Russia, although it’s popular with journalists, politicians, and opposition activists. A report last year estimated that the service had 690,000 active users in Russia, which means any public backlash about the move is likely far less than if the Kremlin had imposed similar restrictions on Instagram or YouTube.

Russia, with a population of 144 million, is also an important market for US Internet companies, and the impending closure provides the Russian government with some economic leverage to respond to the escalating cyber conflict with the United States. American officials said they wanted revenge against Russia, which is hacking a Texas-based company, SolarWinds, that provides software to government and corporate customers.

Recent history could also suggest another explanation for the failure of the Russian government’s websites on Wednesday: botched by a persistent regulator.

In 2018, while trying to shut down the Telegram messaging app, Roskomnadzor accidentally blocked the service for thousands of other websites in Russia. Several Russian government websites, including those of the Kremlin and Parliament, were back online on Wednesday afternoon.