Some of the Russian ads appeared highly sophisticated in their targeting of key demographic groups in areas of the states that turned out to be pivotal, two of the sources said. The ads employed a series of divisive messages aimed at breaking through the clutter of campaign ads online, including promoting anti-Muslim messages, sources said.
Michigan saw the closest presidential contest in the country -- Trump beat Democratic nominee Hillary Clinton by about 10,700 votes out of nearly 4.8 million ballots cast. Wisconsin was also one of the tightest states, and Trump won there by only about 22,700 votes. Both states, which Trump carried by less than 1%, were key to his victory in the Electoral College.