Facing stricter federal oversight, top officials from Facebook and Twitter on Wednesday promised to devote more resources to protecting users from disinformation campaigns by foreign adversaries trying to influence elections.

In advance of the 2018 midterms, Republican and Democratic lawmakers have expressed grave concern over the growing efforts by Russia and Iran to sway U.S. voters. Both Facebook and Twitter say they have shut down troves of accounts linked to politically motivated misinformation campaigns from the countries.