The outlets "spread many types of disinformation, including about both the Pfizer and Moderna vaccines, as well as international organizations, military conflicts, protests, and any divisive issue that they can exploit," the spokeswoman said.
The Wall Street Journal (WSJ) first reported on the identification of the alleged campaign on Sunday. A Kremlin spokesman denied the US claim Russia was spreading false information about vaccines to the WSJ.
Russia's embassy in Washington did not immediately respond to a request for comment.
Russia approved its Sputnik V vaccine in August, before a large-scale trial had begun, saying it was the first country to do so for a COVID-19 shot. Peer-reviewed trials months later proved it was almost 92% effective in fighting the virus.
Pfizer, headquartered in New York, and Germany's BioNTech, produced the first vaccine that was authorized in the United States, which regulators approved in December. The second, made by Moderna, headquartered in Massachusetts, was authorized later that month.
The State Department's Global Engagement Center, set up to counter propaganda and disinformation campaigns, identified the three outlets, the spokeswoman said.
News Front is controlled by Russia's federal security service, the center found. New Eastern Outlook and Oriental Review are directed and controlled by the Russian foreign intelligence service.
A fourth outlet, Rebel Inside, controlled by the Russian army, was also named by the center but is largely dormant, the spokeswoman said.
"The Department will continue to expose Russia’s nefarious activities online," she added. "We will also continue to work closely with our allies and partners to provide a global response to countering disinformation."