(CNN) - CNN reports Russian-linked Facebook ads specifically targeted Michigan and Wisconsin during the 2016 presidential election.
Donald Trump won both states by razor-thin margins, and both were key to his presidential victory.
Michigan had the nation's closest presidential contest.
Sources said some of the ads were very sophisticated in targeting key demographic groups in pivotal areas, according to CNN.
They used a series of divisive messages, some promoting anti-Muslim views.
Congress and Special Counsel Robert Mueller are trying to determine whether trump associates helped the Russians in targeting the ads.
White House officials could not be reached for comment, but have said before they have no knowledge of any Russian involvement in the 2016 election.
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