WASHINGTON — The United States issued new economic sanctions on Monday against seven Russians linked to an internet troll factory in what Secretary of State Mike Pompeo called a warning to foreigners who seek to interfere in American elections.

The penalties were announced as Congress is investigating whether President Trump tried to enlist Ukraine’s leader in a political smear campaign against one of his top Democratic challengers in 2020, former Vice President Joseph R. Biden Jr.

“We have been clear: We will not tolerate foreign interference in our elections,” Mr. Pompeo said in a sharp statement.

“The United States will continue to push back against malign actors who seek to subvert our democratic processes,” Mr. Pompeo continued, “and we will not hesitate to impose further costs on Russia for its destabilizing and unacceptable activities.”