Twitter removed the Russian news agency RIA Novosti from its search results on Monday.
"We see such restrictions by Twitter as an act of censorship of the media, which is directly banned by the Russian Constitution. The social network does not in any way react to our requests, it does not explain its decisions", the Rossiya Segodnya international information agency said in a statement.
"Twitter imposed sanctions on RIA Novosti", the headline says.
Rossiya Segodnya also pointed to Twitter's failure to fairly apply its decision to label state-affiliated media outlets.
"One will not find such labels on the accounts of Voice of America or Radio Free Europe/Radio Liberty. Meanwhile, the personal account of [Sputnik and RT Editor-in-Chief] Margarita Simonyan is labelled as a state-affiliated media outlet. This is supposed to be equality and justice. And the proper 'freedom of speech', how could we do without it", Rossiya Segodnya went on to say.
The news comes after Twitter last month also stopped showing the accounts of RT and Sputnik in the search bar. The platform slapped "state-affiliated media" labels on a number of media organisations – thoughtfully omitting Western outlets like the BBC, Voice of America, or National Public Radio.