The 2012 Russian law now applies only to non-governmental organizations that receive foreign funding and are considered to engage in political activity.
State Duma speaker Vyacheslav Volodin said lawmakers will take up changes to the Russian law on foreign agents to extend it to the media.
"It contradicts both the democracy and freedom of speech principles".
Russian news media and social media actors have come under scrutiny after USA intelligence agencies concluded in January that Russia sought to interfere with the US presidential election to help Donald Trump win.
Simonyan said the head of RT's US subsidiary risked detention and the organization's bank accounts could be frozen if it didn't register.
On Thursday, RT Managing Director Alexey Nikolov said at a meeting of the Provisional Commission of Russia's Federation Council (upper house of parliament) on Information Policy and Media Interaction that he had not registered as a foreign agent in the USA within the period of time set by the United States authorities.
Russian Federation in 2012 passed a controversial law that requires foreign funded non-governmental organizations to register as foreign agents.
Jason Heyward first Cub with consecutive Gold Gloves since Greg Maddux
In addition to a year ago , he previously won in 2012 and 2014 with the Atlanta Braves and in 2015 with the St. The Royals are the only American League team to have at least one victor in each of the past seven seasons.
On Thursday, Alexei Pushkov, chairman of the upper house's Commission on Information Policy and Interaction with Media, held a meeting to discuss the US move and possible retaliatory steps, a Federation Council statement said.
"These are not media, but propaganda tools with 100 percent funding from the US budget", Pushkov was quoted as saying.
San Francisco-based social network Twitter has also angered Russian authorities when it accused RT and the Sputnik news outlet of interfering in the 2016 USA election and banned them from buying ads on its network. Failure to register could result in the seizure of RT's USA bank accounts and the arrest of the senior editor, Simonyan told Russian news outlets.
Russia said last month it had dropped accusations against CNN International of violating Russian media law and that the USA channel could continue broadcasting in Russia.
Last Thursday, Twitter announced it would drop advertising by RT and Sputnik-owned accounts on its network due to their alleged meddling in the US presidential election past year.
Russian President Vladimir Putin signaled that he would sign such a law last month, when he told a conference of foreign policy scholars that Russia would respond immediately and reciprocally to "any efforts to limit our mass media".
Human rights groups have condemned the label, who say it echoes Soviet-era attacks on dissidents.
Vyacheslav Volodin, the speaker of the State Duma, said parliament could back legislation as early as next week in response to what lawmakers view as USA pressure on Russian media.