The company used "visibility filtering rules" in order to curtail propaganda and misinformation. Under Elon Musk, those guidelines have been discarded.
The social network is flagging publishers it says are under 'editorial control' of governments, as part of efforts to secure its platform against foreign influence campaigns.
Moscow has made it clear that the move comes in direct retaliation for the U.S. Justice Department's decision to require the Kremlin-funded RT America to register as a "foreign agent."
The microblog service announced the move "effective immediately" ahead of a congressional hearing about Russia's use of social media in its influence campaign.
Critics have long raised concerns about Gen. Michael Flynn's relationship with Moscow. The nominee for national security adviser was in regular contact in December with Russia's ambassador to the U.S.