A group of 20 Democrats from the House and Senate are urging the Federal Election Commission to come up with new rules to prevent foreign actors from using platforms like Twitter and Facebook to influence U.S. elections.

Sixteen Democratic senators and four members of the House sent a letter to FEC Chairman Steven Walther on Wednesday following revelations Russian actors used Facebook as part of its efforts to influence the 2016 election.

"Foreign political activity is a direct assault on federal election law and the integrity of our elections," the Democrats wrote.

"Social media platforms offer the ability to target millions of users based upon a wealth of highly-detailed information. As we have seen, the low cost of reaching these users equips hostile foreign actors with a powerful new tool for disruption of our democratic process. Therefore, it is incumbent that the commission take immediate action to preserve the integrity of our election law and our elections."

Facebook announced earlier this month it discovered $100,000 in ad spending tied to 470 fake accounts connected to a Russian "troll farm" known for spreading pro-Kremlin propaganda. The ads ran on the platform from June 2015 and May 2017.

Facebook reported its findings to special counsel Robert Mueller, who is leading the federal probe into Russian meddling, and both Facebook and Twitter are expected to speak with the Senate Intelligence Committee.

The Democratic coalition urged the FEC to begin working on guidance addressing how platforms can do more to prevent foreign actors from spending money on ads to influence future U.S. elections, particularly with the coming 2018 midterm elections.

"Our concerns do not lie with American citizens, interest groups, campaigns, or political action committees engaging in their Constitutional right to freely discuss the ideas and issues of the day to effectuate political or social change," the Democrats wrote. "Rather, we must address the threat posed by foreign citizens, companies, or organizations who aim to illegally interfere with our political process."