The threat of foreign adversaries such as Russia trying to influence U.S. politicians, campaigns and the public "continues to grow," with elections presenting an especially attractive target, Deputy Attorney General Rod Rosenstein said.

"Influence operations are a form of information warfare," Rosenstein said in prepared remarks for a speech Thursday at the Aspen Security Forum in Colorado. "Covert propaganda and disinformation are among the primary weapons."

Elections, in particular, provide "an attractive opportunity for foreign influence campaigns to undermine our political processes," Rosenstein said. The deputy attorney general cited comments by Director of National Intelligence Dan Coats, who said last week that "the digital infrastructure that serves this country is literally under attack."