According to ABC News, Sanders is gaining 47% of the vote, second place is held by former US vice president Joe Biden with 23%, and third by former mayor of South Bend (Indiana) Pete Buttigic with 14%.
This is followed by Massachusetts Senator Elizabeth Warren with 9% and California billionaire Tom Styer 4% and Amy Klobushar with 3%.
Sanders had earlier called on Russia to "stay away from American elections."
On February 21, The New York Times reported that US intelligence warned of alleged "Russian interference" in the 2020 presidential campaign to help American leader Donald Trump reelect for a second term.
Trump called these messages another "disinformation campaign."
US Presidential Adviser on National Security Robert O'Brien said he was not aware of any attempts by Russia to support the American leader in the elections.