United States lawmakers questioned representatives of Facebook, Twitter and Google over Russian efforts to influence the 2016 presidential election. The U.S. Congress is investigating how Russia used the companies’ internet services to spread disinformation during the election. Congress also asked how the companies planned to stop the misuse of their services in the future. Senate Intelligence Chairman Richard Burr of North Carolina spoke to lawyers from the three companies at a hearing on Wednesday. He said media reports suggested that Russian-linked Facebook advertisements directly influenced the election’s outcome. The reports claim Russian government agents spent as much as $100,000 on Facebook advertisements. You must do better to protect the American people andall of your users from this kind of manipulation, Burr said. Senator Dianne Feinstein of California argued that social media companies are responsible for the material placed on their websites.