Russian State Duma speaker Vyacheslav Volodin, center, with other officials during a session Nov. 15. (Ilnitsk/Epa-Efe/Rex/Shutterstock/Ilnitsk/Epa-Efe/Rex/Shutterstock)

Russian lawmakers declared Friday that they probably will ban all U.S. media from entering both houses of the Russian parliament in retaliation for a U.S. decision to block Moscow-funded broadcaster RT from Congress.

The decision — which could come as early as next week — is part of escalating tit-for-tat actions that began in October with a Justice Department order to add RT to a list of media entities that must register as foreign agents.

The Russian ban would affect at least 21 news outlets, the Russian news agency Interfax said, citing a government list of accredited U.S.-based news organizations. They include state-funded Radio Free Europe and Voice of America, private news agencies such as Bloomberg News and the Associated Press, and other media entities including The Washington Post, the New York Times, CNN, CBS and NBC.

The lower house of parliament, or Russian State Duma, faces the Kremlin in downtown Moscow and is a popular destination for U.S. correspondents covering major legislation or seeking comment from a lawmaker.

Olga Savastyanova, head of the committee that manages access to the Duma, told reporters that under proposed new rules, "journalists from all U.S. media outlets will be prohibited from visiting the State Duma."

Russia's upper house of parliament, the Federation Council, quickly followed suit. A Kremlin spokesman supported the measure, saying he had "full understanding" of the Duma's move to bar U.S. reporters.

The ban came after a Washington correspondents' group unanimously decided to revoke the accreditation of RT, formerly known as Russia Today, after the network's operating company was registered as a foreign agent.

The Senate Rules and Administration Committee and the Office of the Speaker of the House had been notified that the withdrawal of RT's accreditation is "effective immediately," noted a letter the correspondents' group sent to RT.

Russian officials responded angrily, saying they would take steps to limit the activities of U.S. media organizations in Russia. Last month, President Vladi­mir Putin signed legislation into law allowing the Russian Justice Ministry to force foreign news agencies to register under existing legislation as foreign agents, under penalty of fines or a ban on their work.

Russian officials have said they will continue to impose mirror restrictions on U.S. news media, although the list of banned entities is far larger, and U.S. officials tend to call RT a propaganda network rather than a news agency.

"The reason is the decision to strip Russia Today of its accreditation," Savastyanova told reporters Friday, adding that the case related to "the inadmissibility of the encroachment on democratic values, free speech and the right to receive impartial information."