Russian authorities warned that they could retaliate against U.S.-based media and social networks if state-backed Russian channel RT's access to social networks is restricted, a threat that came amid what the network called a "war" targeting its digital reach.

The January 19 warning from the state communications oversight agency, Roskomnadzor, came after RT said it had been "blocked from posting content to its Facebook page" until late on January 21, a time period that it emphasized includes U.S. President-elect Donald Trump's inauguration.

RT suggested that Current Time TV, a Russian-language network run by RFE/RL in cooperation with VOA, was at least partly to blame.

Current Time denied any involvement.

Facebook said later on January 19 that RT's access had been fully restored and said it was entirely inaccurate to suggest the temporary block was linked in any way to outside factors or events.

"We are looking into the reasons behind the temporary block," a Facebook spokesperson told RFE/RL in an e-mailed statement. RT said that the "as yet unexplained blackout" lasted about 20 hours.

In the warning a few hours earlier, Roskomnadzor chief Aleksandr Zharov said that "if the unprecedented pressure put on RT by American media and social networks leads to restrictions on the work of the Russian TV channel, we will have to take active measures in response."

"Many American media outlets work in Russia, including television channels, [and their] rights and responsibilities are equal to those of other media outlets," Russian state news agency RIA quoted Zharov as saying. He did not mention any specifics.

'This Is War'

The Facebook blockage coincided with claims by RT that it had received an inquiry from YouTube asking if the network or any of its employees were under sanctions, and that a U.S.-based web analytics company, Dataminr, had terminated its contract with RT without explanation.

The claims by the network come amid heightened scrutiny of RT’s role in the American political landscape after U.S. intelligence this month accused it of serving as a pillar of a Kremlin campaign to meddle in the November 8 presidential election.

Both the Kremlin and RT have dismissed the allegations, including that the alleged interference was aimed at helping President-elect Donald Trump defeat Hillary Clinton in the election, as ludicrous.

U.S. officials have accused the network, which Russian President Vladimir Putin has said should try "to break the Anglo-Saxon monopoly on the global information streams," of being little more than a Kremlin propaganda arm, a charge RT rejects.

Responding to YouTube's alleged inquiry concerning sanctions, RT Editor in Chief Margarita Simonyan wrote on Twitter: "This is war."

Simonyan is also the editor in chief of Russia's state media behemoth Rossiya Segodnya. The media holding's director, prominent television anchor Dmitry Kiselyov, was among numerous Russian officials sanctioned by the EU in response to Russia’s 2014 annexation of Ukraine’s Crimean Peninsula.

The EU sanctions largely mirror those imposed by the United States, though Washington has not slapped Kiselyov or RT employees with the visa bans and asset freezes mandated by the sanctions.

Neither YouTube nor Dataminr immediately responded to requests for comment on January 19.

Facebook Furor

RT said that a "misplaced live streaming rights strike" during its broadcast of President Barack Obama's final news conference on January 18 appeared to have "triggered the ban" on elements of its Facebook page, suggesting it believes it was wrongly accused of copyright violations.

In a report on its website, it added that Simonyan "said she wasn't surprised that RT had been blocked from posting on Facebook following a complaint from Current Time TV."

Current Time said it was not involved in any way.

"Our channel did not file any complaints regarding RT's transmission of the Obama press conference," said Current Time's acting director, Daisy Sindelar. "The blocking of RT is not the result of any action on our part."

Responding to a question from RT about the issue during a regular news briefing on January 19, Russian Foreign Ministry spokeswoman Maria Zakharova urged the channel to make a detailed appeal to international free-speech protection groups and also seek "official responses from organizations that blocked...broadcasts."

Zakharova said that Russia "regularly encounters attempts to use technical pretexts to block not only the TV channel RT but other Russian media outlets as well," alleging that "all methods are used -- from censorship without explanation to thought-up reasons," state news agency TASS reported.

The RT report referred to Current Time as "a part of Radio Liberty, financed by the U.S. Department of State."

RFE/RL is an independent corporation funded by the U.S. Congress. The U.S. government is not involved in its operational or editorial decisions.

With reporting by Carl Schreck in Washington