Moscow: The Kremlin on Friday criticised "unprecedented pressure" on Russian media in the United States and warned of possible reciprocal action.
The US Department of Justice has ordered the state-funded RT media group, a television channel which broadcasts in English and other languages, to register as a "foreign agent" under the Foreign Agents Registration Act (FARA).
The television network is increasingly viewed in Washington as a Kremlin propaganda tool used to interfere in the 2016 US presidential polls.
According to RT, the channel has been given a deadline of October 17 to register under FARA, a law written in 1938 to blunt Nazi propaganda, which specifically exempts news organisations.
Foreign agent status could mean that the channel would have to make personal information about its employees and interviewees public, RT editor-in-chief Margarita Simonyan said yesterday.
"If we don't... our employees and property will be arrested," she said, calling it "de-facto expulsion from the country."
State news agency Sputnik, which has the same management as RT, is also under FBI investigation, according to reports.
"Some of our media is faced with unprecedented pressure," Kremlin spokesman Dmitry Peskov told journalists.
"We believe this is being done in violation of freedom of speech (and) freedom of the media."
"Clearly, in the case of continued pressure, continued violation of the rights of our media to work unimpeded, I cannot rule out that actions will be taken in accordance with the principle of reciprocity."
Russian media reports said prosecutors are considering retaliatory measures against US media.
Russia's media watchdog chief yesterday said it found CNN in violation of the country's media law over a technicality and issued an official warning.
At a senate committee meeting on defending state sovereignty, Simonyan said: "People are quitting in droves...
it's hard to even find a stringer in the US."
She added that YouTube has kicked the channel off the list of 'Google Preferred' premium video channels for advertisers.
"Clearly this is a result of pressure," she said.
Senate committee chairman Andrei Klimov said "it's time to think about concrete retaliatory measures" to US actions.